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AMERICAN ADDRESSES.
^'AMERICAN ADDRESSES//
LECTURE ON THE STUDY OF BIOLOGY.
THOMAS H. 'HUXLEY./
" Naturae leges et regulse, secundum quas omnia fiunt et ex imis
formis in alias mutantur, sunt ubique et semper eadem."
B. DE Spinoza, Ethices, Pars lertia, Proefatio.
NEW YORK:
D. APPLETON AND COMPANY,
I, 3, AND 5 BOND STREET.
1888.
347
m74-
COPYRIGHT BY
D. APTLETON AND COMPANY,
ElEaaONIC VERSION
. AVAILABLB
N(5. „
CONTENTS.
I.— THREE LECTURES ON EVOLUTION (New York,
September i8, 20, 22, 1876).
LECTURE I.— The Three Hypotheses respecting
THE History of Nature . , . Page i
LECTURE II.- The Hypothesis of Evolution.
The Neutral and the Favour-
able Evidence Page 31
LECTURE III.— The Demonstrative Evidence of
Evolution Page 71
IL— AN ADDRESS ON THE OCCASION OF THE
OPENING OF THE JOHNS HOPKINS UNIVER-
SITY (Baltimore, September 12, 1876) . . Page 97
IIL— A LECTURE ON THE STUDY OF BIOLOGY, IN
CONNECTION WITH THE LOAN COLLECTION
OF SCIENTIFIC APPARATUS (South Kensington
Museum, December 16, 1876) . . . . Page 129
NEW YORK.
LECTURES ON EVOLUTION.
LECTURES ON EVOLUTION.
LECTURE I.
THE THREE HYPOTHESES RESPECTING THE
HISTORY OF NATURE.
We live in and form part of a system of things
of immense diversity and perplexity, which we call
Nature; and it is a matter of the deepest interest
to all of us that we should form just conceptions
of the constitution of that system and of its past
liistory. With relation to this universe, man is,
in extent, little more than a mathematical point ; in
duration but a fleeting shadow ; he is a mere reed
shaken in the winds of force. But, as Pascal long
ago remarked, although a mere reed, he is a thinking
reed ; and in virtue of that wonderful capacity of
thought, he has the power of framing for himself a
symbolic conception of the universe, which, although
doubtless highly imperfect and inadequate as a pic-
ture of the great whole, is yet sufficient to serve
2 LECTURES ON EVOLUTION. [lect. i.
him as a chart for the guidance of his practical
affairs. It has taken long ages of toilsome and
often fruidess labour to enable man to look steadily
at the shifting scenes of the phantasmagoria of
Nature, to nodce what is fixed amono- her fluctua-
tions, and what is regular among her apparent
irregularides ; and it is only comparatively lately,
within the last few centuries, that the conception
of a universal order and of a definite course of
things, which we term the course of Nature, has
emerged.
But, once originated, the conception of the con-
stancy of the order of Nature has become the
dominant idea of modern thought. To any person
who is familiar with the facts upon which that con-
ception is based, and is competent to estimate their
significance, it has ceased to be conceivable that
chance should have any place in the universe, or
that events should depend upon any but the natural
sequence of cause and effect. We have come to
look upon the present as the child of the past and
as the parent of the future; and, as we have
excluded chance from a place in the universe, so
we ignore, even as a possibility, the notion of any
interference with the order of Nature. Whatever
may be men's speculative doctrines, it is quite
certain that every intelligent person guides his life
and risks his fortune upon the belief that the order
LECT. I.] THE THREE HYPOTHESES. 3
of Nature is constant, and that the chain of natural
causation is never broken.
In fact, no behef which we entertain has so com-
plete a logical basis as that to which I have just
referred. It tacitly underlies every process of
reasoning ; it is the foundation of every act of the
will. It is based upon the broadest induction, and
it is verified by the most constant, regular, and
universal of deductive processes. But we must
recollect that any human belief, however broad its
basis, however defensible it may seem, is, after all,
only a probable belief, and that our widest and
safest generalizations are simply statements of the
highest degree of probability. Though we are
quite clear about the constancy of the order of
Nature, at the present time, and in the present
state of things, it by no means necessarily follows
that we are justified in expanding this generalisa-
tion into the infinite past, and in denying, abso-
lutely, that there may have been a time when
Nature did not follow a fixed order, when the
relations of cause and effect were not definite, and
when extra-natural agencies interfered with the
general course of Nature, Cautious men will
allow that a universe so different from that which
we know may have existed ; just as a very candid
thinker may admit that a world in which two and
two do not make four, and in which two straight
LECTURES ON EVOLUTION. [lect. i.
lines do inclose a space, may exist. But the
same caution which forces the admission of such
possibilities demands a great deal of evidence
before it recognises them to be anything more sub-
stantial. And when it is asserted that, so many
thousand years ago, events occurred in a manner
utterly foreign to and inconsistent with the exist-
ing laws of Nature, men, who without being
particularly cautious, are simply honest thinkers,
unwilling to deceive themselves or delude others,
ask for trustworthy evidence of the fact.
Did things so happen or did they not ? This
is a historical question, and one the answer to
which must be sought in the same way as the
solution of any other historical problem.
So far as I know, there are only three hypotheses
which ever have been entertained, or which well
can be entertained, respecting the past history of
Nature. I will, in the first place, state the hypo-
theses, and then I will consider what evidence
bearing upon them is in our possession, and by
what light of criticism that evidence is to be
interpreted.
■ Upon the first hypothesis, the assumption is, that
phenomena of Nature similar to those exhibited by
the present world have always existed ; in other
words, that the universe has existed from all
LECT. I.] THE THREE HYPOTHESES. 5
eternity In what may be broadly termed its present
condition.
The second hypothesis is, that the present state
of things has had only a limited duration ; and that,
at some period In the past, a condition of the world,
essentially similar to that which we now know,
came Into existence, without any precedent condi-
tion from which It could have naturally proceeded.
The assumption that successive states of Nature
have arisen, each without any relation of natural
causation to an antecedent state, Is a mere modifi-
cation of this second hypothesis.
The third hypothesis also assumes that the pre-
sent state of things has had but a limited duration ;
but it supposes that this state has been evolved by
a natural process from an antecedent state, and that
from another, and so on ; and, on this hypothesis,
the attempt to assign any limit to the series of
past changes Is, usually, given up.
It is so needful to form clear and distinct notions
of what is really meant by each of these hypotheses
that I will ask you to Imagine what, according to
each, would have been visible to a spectator of the
events which constitute the history of the earth.
On the first hypothesis, however far back In time
that spectator might be placed, he would see a
world essentially, though perhaps not in all Its
details, similar to that which now exists. The
LECTURES ON EVOLUTION. [lect. i.
animals which existed would be the ancestors of
those which now live, and similar to them ; the
plants, in like manner, would be such as we know ;
and the mountains, plains, and waters would fore-
shadow the salient features of our present land and
water. This view was held more or less distinctly,
sometimes combined with the notion of recurrent
cycles of change, in ancient times ; and its influence
has been felt down to the present day. It is worthy
of remark that it is a hypothesis which is not incon-
sistent with the doctrine of Uniformitarianism, with
which geologists are familiar. That doctrine was
held by Hutton, and in his earlier days by Lyell.
Hutton was struck by the demonstration of astrono-
mers that the perturbations of the planetary bodies,
however great they may be, yet sooner or later
right themselves ; and that the solar system pos-
sesses a self-adjusting power by which these aber-
rations are all brought back to a mean condition.
Hutton imaeined that the like mio^ht be true of
terrestrial changes ; althouo:h no one recognised
more clearly than he the fact that the dry land is
being constantly washed down by rain and rivers
and deposited in the sea ; and that thus, in a longer
or shorter time, the inequalities of the earth's sur-
face must be levelled, and its high lands brought
down to the ocean. But, taking into account the
internal forces of the earth, which, upheaving the
LECT. I.] THE MILTONIC HYPOTHESIS.
sea-bottom give rise to .new land, he thought that
these operations of degradation and elevation might
compensate each other ; and that thus, for any
assignable time, the general features of our planet
might remain what they are. And inasmuch as,
under these circumstances, there need be no limit
to the propagation of animals and plants, it is
clear that the consistent working-out of the uni-
formitarian idea might lead to the conception of the
eternity of the world. Not that I mean to say
that either Hutton or Lyell held this conception —
assuredly not ; they would have been the first to
repudiate it. Nevertheless, the logical development
of their arguments tends directly towards this
hypothesis.
The second hypothesis supposes that the present
order of things, at some no very remote time, had
a sudden origin, and that the world, such as it
now is, had chaos for its phenomenal antece-
dent That is the doctrine which you will find
stated most fully and clearly in the immortal poem
of John Milton — the English Divina Commedia —
Paradise Lost. I believe it is largely to the in-
fluence of that remarkable work, combined with the
daily teachings to which we have all listened in
our childhood, that this hypothesis owes its general
wide diffusion as one of the current beliefs of
English-speaking people. If you turn to the
8 LECTURES ON EVOLUTION. [lect. i.
seventh book of Paradise LosY;<^you will find there
stated the hypothesis to which '1 refer, which is
briefly this : That this visible universe of ours came
into existence at no great distance of time from the
present ; and that the parts of which it is composed
made their appearance, in a certain definite order,
in the space of six natural days, in such a manner
that, on the first of these days, light appeared ; that,
on the second, the firmament, or sky, separated the
waters above, from the waters beneath the firma-
ment ; that, on the third day, the waters drew away
from the dry land, and upon it a varied vegetable
life, similar to that which now exists, made its ap-
pearance ; that the fourth day was signalised by the
apparition of the sun, the stars, the moon, and the
planets ; that, on the fifth day, aquatic animals
originated within the waters ; that, on the sixth
day, the earth gave rise to our four-footed terres-
trial creatures, and to all varieties of terrestrial
animals except birds, which had appeared on the
preceding day ; and, finally, that man appeared upon
the earth, and the emergence of the universe from
chaos was finished. Mihon tells us, without the
least ambiguity, what a spectator of these marvel-
lous occurrences would have witnessed. I doubt
not that his poem is famih'ar to all of you, but I
should like to recall one passage to your minds, in
order that I may be justified in what I have said
LECT. I.] THE MILTONIC HYPOTHESIS. 9
regarding the perfectly concrete, definite picture of
the origin of the animal world which Milton draws.
He says : —
" The sixth, and of creation last, arose
With evening harps and matin, when God said,
' Let the earth bring forth soul Hving in her kind.
Cattle and creeping things, and beast of the earth,
Each in their kind ! ' The earth obeyed, and, straight
Opening her fertile womb, teemed at a birth
Innumerous living creatures, perfect forms,
Limbed and full-grown. Out of the ground uprose,
As from his lair, the wild beast, where he wons
In forest wild, in thicket, brake, or den ;
Among the trees in pairs they rose, they walked ;
The cattle in the fields and meadows green ;
Those rare and solitary ; these in flocks
Pasturing at once, and in broad herds upsprung.
The grassy clods now calved ; now half appears
The tawny lion, pawing to get free
His hinder parts — then springs, as broke from bonds.
And rampant shakes his brinded mane ; the ounce,
The libbard, and the tiger, as the mole
Rising, the crumbled earth above them threw
In hillocks ; the swift stag from underground
Bore up his branching head ; scarce from his mould
Behemoth, biggest born of earth, upheaved
His vastness ; fleeced the flocks and bleating rose
As plants ; ambiguous between sea and land.
The river-horse and scaly crocodile.
At once came forth whatever creeps the ground,
Insector worm."
There is no doubt as to the meaning of this
statement, nor as to what a man of Milton's genius
expected would have been actually visible to an
eye-witness of this mode of origination of living
thines.
lo LECTURES ON EVOLUTION. [lect. i.
The third hypothesis, or the hypothesis of evolu-
tion, supposes that, at any comparatively late period
of past time, our imaginary spectator would meet
with a state of things very similar to that which now
obtains ; but that the likeness of the past to the pre-
sent would gradually become less and less, in propor-
tion to the remoteness of his period of observation
from the present day ; that the existing distribution
of mountains and plains, of rivers and seas, would
show itself to be the product of a slow process
of natural change operating upon more and more
widely different antecedent conditions of the mineral
framework of the earth ; until, at length, in place
of that framework, he would behold only a vast
nebulous mass, representing the constituents of the
sun and of the planetary bodies. Preceding the
forms of life which now exist, our observer would
see animals and plants not identical with them, but
like them ; increasing their differences with their
antiquity and, at the same time, becoming simpler
and simpler; until, finally, the world of life would
present nothing but that undifferentiated protoplasmic
matter which, so far as our present knowledge goes,
is the common foundation of all vital activity.
The hypothesis of evolution supposes that in all
this vast progression there would be no breach of
continuity, no point at which we could say " This
a natural process," and " This is not a natural
LECT. I.] HISTORICAL EVIDENCE.
process ; " but that the whole might be compared to
that wonderful process of development which may
be seen going on every day under our eyes, in
virtue of which there arises, out of the semi-fluid,
comparatively homogeneous substance which we call
an egg, the complicated organization of one of the
higher animals. That, in a few words, is what is
meant by the hypothesis of evolution.
I have already suggested that in dealing with
these three hypotheses, in endeavouring to form a
judgment as to which of them is the more worthy
of belief, or whether none is worthy of belief — in
which case our condition of mind should be that
suspension of judgment which is so difficult to all
but trained intellects — we should be indifferent to
all a priori considerations. The question is a
question of historical fact. The universe has come
into existence somehow or other, and the problem
is, whether it came into existence in one fashion,
or whether it came into existence in another ; and,
as an essential preliminary to further discussion,
permit me to say two or three words as to the
nature and the kinds of historical evidence.
The evidence as to the occurrence of any event
in past time may be ranged under two heads which,
for convenience' sake, I will speak of as testimonial
evidence and as circumstantial evidence. By testi-
12 LECTURES ON EVOLUTION. [lect. i
monial evidence I mean human testimony ; and by
circumstantial evidence I mean evidence which is
not human testimony. Let me illustrate by a
familiar example what I understand by these two
kinds of evidence, and what is to be said respecting
their value.
Suppose that a man tells you that he saw a
person strike another and kill him ; that is testi-
monial evidence of the fact of murder. But it is
possible to have circumstantial evidence of the fact
of murder ; that is to say, you may find a man
dying with a wound upon his head having exactly
the form and character of the wound which is made
by an axe, and, with due care in taking surrounding
circumstances into account, you may conclude with
the utmost certainty that the man has been mur-
dered ; that his death is the consequence of a blow
inflicted by another man with that implement. We
are very much in the habit of considering circum-
stantial evidence as of less value than testimonial
evidence, and it may be that, where the circum-
stances are not perfectly clear and intelligible, it is
a dangerous and unsafe kind of evidence ; but it
must not be forgotten that, in many cases, cir-
cumstantial is quite as conclusive as testimonial
evidence, and that, not unfrequentl y, it is a great
deal weightier than testimonial evidence. For ex-
ample, take the case to which I referred just now.
LECT. I.] THE FIRST HYPOTHESIS. 13
The circumstantial evidence may be better and
more convincing than the testimonial evidence ; for it
may be impossible, under the conditions that I have
defined, to suppose that the man met his death
from any cause but the violent blow of an axe
wielded by another man. The circumstantial evi-
dence in favour of a murder having been com-
mitted, in that case, is as complete and as con-
vincing as evidence can be. It is evidence which
is open to no doubt and to no falsification. But
the testimony of a witness is open to multitudi-
nous doubts. He may have been mistaken. He
may have been actuated by malice. It has con-
stantly happened that even an accurate man has
declared that a thing has happened in this, that, or
the other way, when a careful analysis of the cir-
cumstantial evidence has shown that it did not
happen in that wa}^, but in some other way.
We may now consider the evidence in favour
of or against the three hypotheses. Let me first
direct your attention to what is to be said about
the hypothesis of the eternity of the state of things
in which we now live. What will first strike you
is, that it is a hypothesis which, whether true or
false, is not capable of verification by any evidence.
For, in order to obtain either circumstantial or testi-
monial evidence sufficient to prove tlie eternity of
duration of the present state of nature, you must
14 LECTURES ON EVOLUTION. ftEcx. r.
have an eternity of witnesses or an infinity of
circumstances, and neither of these is attainable.
It is utterly impossible that such evidence should
be carried beyond a certain point of time ; and all
that could be said, at most, would be, that so far
as the evidence could be traced, there was nothing,
to contradict the hypothesis. But when you look,
not to the testimonial evidence — which, considering
the relative insignificance of the antiquity of human
records, might not be good for much in this case —
but to the circumstantial evidence, then you find
that this hypothesis is absolutely incompatible with
such evidence as we have ; which is of so plain
and so simple a character that it is impossible in
any way to escape from the conclusions which it
forces upon us.
You are, doubtless, all aware that the outer sub-
stance of the earth, which alone is accessible to
direct observation, is not of a homogeneous cha-
racter, but that it is made up of a number of
layers or strata, the titles of the principal groups of
which are placed upon the accompanying diagram.
Each of these groups represents a number of beds
of sand, of stone, of clay, of slate, and of various
other materials.
On careful examination, it is found that the
materials of which each of these layers of more
or less hard rock are composed are, for the most
LFCT. 1.1
THE STRATIFIED ROCKS.
15
Post-Tertiai-y and Recent.
Pliocene.
Miocene.
Eocene.
Cretaceous.
'^^S Jurassic or Oolitic.
p .....Triassic (New Red Sandstone).
Permian.
Carboniferous.
^.... Devonian or Old Red Sandstone.
...Silurian.
'- — I -•• Cambrian.
;_ ,-1 .... Iluronian.
Laurentian.
Fiu. I. — Ii)K.\L Skciio.n of thk Crust of the Earth.
i6 LECTURES ON EVOLUTION. [lect. i.
part, of the same nature as those which are at pre-
sent being formed under known conditions on the
surface of the earth. For example, the chalk, which
constitutes a great part of the Cretaceous formation
in some parts of the world, is practically identical
in its physical and chemical characters with a sub-
stance which is now being formed at the bottom
of the Atlantic Ocean, and covers an enormous
area ; other beds of rock are comparable with the
sands which are being formed upon sea-shores,
packed together, and so on. Thus, omitting rocks
of igneous origin, it is demonstrable that all these
beds of stone, of which a total of not less than
seventy thousand feet is known, have been formed
by natural agencies, either out of the waste and
washing of the dry land, or else by the accumula-
tion of the exuviae of plants and animals. Many
of these strata are full of such exuviae — the so-
called " fossils." Remains of thousands of species
of animals and plants, as perfectly recognisable as
those of existing forms of life which you meet
with in museums, or as the shells which you pick
up upon the sea-beech, have been imbedded in
the ancient sands, or muds, or limestones, just as
they are being imbedded now, In sandy, or clayey,
or calcareous subaqueous deposits. They furnish
us with a record, the general nature of which can-
not be misinterpreted, of the kinds of things that
LECT. I.] THE MILTONIC HYPOTHESIS. 17
have lived upon the surface of the earth during
the time that is registered by this great thickness
of stratified rocks. But even a superficial study of
these fossils shows us that the animals and plants
which live at the present time have had only a tem-
porary duration ; for the remains of such modern
forms of life are met with, for the most part, only in
the uppermost or latest tertiaries, and their number
rapidly diminishes in the lower deposits of that
epoch. In the older tertiaries, the places of existing
animals and plants are taken by other forms, as
numerous and diversified as those which live now
in the same localities, but more or less different from
them ; in the mesozoic rocks, these are replaced by
others yet more divergent from modern types ; and
in the palaeozoic formations the contrast is still more
marked. Thus the circumstantial evidence abso-
lutely negatives the conception of the eternity of
the present condition of things. We can say with
certainty that the present condition of things has
existed for a comparatively short period ; and that,
so far as animal and vegetable nature are concerned,
it has been preceded by a different condition. We
can pursue this evidence until we reach the lowest
of the stratified rocks, in which we lose the indications
of life altogether. The hypothesis of the eternity
of the present state of nature may therefore be
put out of court.
LECTURES ON EVOLUTION. [lect. l
We now come to what I will term Milton's
hypothesis — the hypothesis that the present
condition of things has endured for a comparatively
short time ; and, at the commencement of that time,
came into existence within the course of six days.
I doubt not that it may have excited some surprise
in your minds that I should have spoken of this as
Milton's hypothesis, rather than that I should have
chosen the terms which are more customary, such as
"the doctrine of creation," or "the Biblical doctrine,"
or "the doctrine of Moses," all of which denomina-
tions, as applied to the hypothesis to which I have
just referred, are certainly much more familiar to
you than the title of the Miltonic hypothesis. But
I have had what I cannot but think are very
weighty reasons for taking the course which I have
pursued. In the first place, I have discarded the
title of the " doctrine of creation," because my
present business is not with the question why
the objects which constitute Nature came into ex-
istence, but when they came into existence, and in
what order. This is as strictly a historical question
as the question when the Angles and the Jutes in-
vaded England, and whether they preceded or fol-
lowed the Romans. But the question about creation
is a philosophical problem, and one which cannot
be solved, or even approached, by the historical
method. What we want to learn is, whether the
LECT. 1.] THE MILTONIC HYPOTHESIS. 19
facts, so far as they are known, afford evidence that
things arose in the way described by Milton, or
whether they do not ; and, when that question is
settled, it will be time enough to inquire into the
causes of their origination.
In the second place, I have not spoken of this
doctrine as the Biblical doctrine. It is quite true
that persons as diverse in their general views as
Milton the Protestant and the celebrated Jesuit
Father Suarez, each put upon the first chapter of
Genesis the interpretation embodied in Milton's
poem. It is quite true that this interpretation is
that which has been instilled into every one of us
in our childhood ; but I do not for one moment
venture to say that it can properly be called the
Biblical doctrine. It is not my business, and does
not lie within my competency, to say what the
Hebrew text does, and what it does not signify ;
moreover, were I to affirm that this is the Biblical
doctrine, I should be met by the authority of many
eminent scholars, to say nothing of men of science,
who, at various times, have absolutely denied that
any such doctrine is to be found in Genesis. If we
are to listen to many expositors of no mean authority,
we must believe that what seems so clearly defined
in Genesis — as if very great pains had been taken
that there should be no possibility of mistake —
is not the meaning of the text at all. The account
LECTURES ON EVOLUTION. [lect. i.
is divided into periods that we may make just as
long or as short as convenience requires. We are
also to understand that it is consistent with the
original text to believe that the most complex plants
and animals may have been evolved by natural
processes, lasting for millions of years, out of struc-
tureless rudiments. A person who is not a Hebrew
scholar can only stand aside and admire the mar-
vellous flexibility of a language which admits of
such diverse interpretations. But assuredly, in the
face of such contradictions of authority upon matters
respecting which he is incompetent to form any
judgment, he will abstain, as I do, from giving any
opinion.
In the third place, I have carefully abstained
from speaking of this as the Mosaic doctrine, be-
cause we are now assured upon the authority of the
highest critics, and even of dignitaries of the Church,
that there is no evidence that Moses wrote the
Book of Genesis, or knew anything about it. You
will understand that I give no judgment — it would
be an impertinence upon my part to volunteer even
a suggestion — upon such a subject. But, that being
the state of opinion among the scholars and the
clergy, it is well for the unlearned in Hebrew lore,
and for the laity, to avoid entangling themselves in
such a vexed question. Happily, Milton leaves us
no excuse for doubting what he means, and I shall
LECT. I.] THE MILTONIC HYPOTHESIS. 2i
therefore be safe in speaking of the opinion in
question as the Mil tonic hypothesis.
Now we have to test that hypothesis. For my
part, I have no prejudice one way or the other. If
there is evidence in favour of this view, I am bur-
dened by no theoretical difficulties in the way of
accepting it ; but there must be evidence. Scientific
men get an awkward habit — no, I won't call it that,
for it is a valuable habit — of believing nothing
unless there is evidence for it ; and they have a
way of looking upon belief which is not based
upon evidence, not only as illogical, but as im-
moral. We will, if you please, test this view by
the circumstantial evidence alone ; for, from what
I have said, you will understand that I do not
propose to discuss the question of what testi-
monial evidence is to be adduced in favour of it.
If those whose business it is to judge are not at
one as to the authenticity of the only evidence of
that kind which is offered, nor as to the facts to
which it bears witness, the discussion of such
evidence is superfluous.
But I may be permitted to regret this necessity
of rejecting the testimonal evidence the less, because
the examination of the circumstantial evidence leads
to the conclusion, not only that it is incompetent to
justify the hypothesis, but that, so far as it goes,
it is contrary to the hypothesis.
2 2 LECTURES ON EVOLUTION. [lect. i.
The considerations upon which I base this con-
clusion are of the simplest possible character. The
Miltonic hypothesis contains assertions of a very
definite character relatinor to the succession of Vivino:
forms. It is stated that plants, for example, made
their appearance upon the third day, and not before.
And you will understand that what the poet means
by plants are such plants as now live, the an-
cestors, in the ordinary way of propagation of like
by like, of the trees and shrubs which flourish in
the present world. It must needs be so ; for, if
they were different, either the existing plants have
been the result of a separate origination since that
described by Milton, of which we have no re-
cord, nor any ground for supposition that such an
occurrence has taken place; or else they have
arisen by a process of evolution from the original
stocks.
In the second place, it is clear that there was
no animal life before the fifth day, and that, on
the fifth day, aquatic animals and birds appeared.
And it is further clear that terrestrial living things,
other than birds, made their appearance upon the
sixth day, and not before. Hence, it follows that,
if, in the large mass of circumstantial evidence as
to what really has happened in the past history of
the globe we find indications of the existence of
terrestrial animals, other than birds, at a certain
I.ECT. I.] THE MILTONIC HYPOTHESIS. "^23
period, it is perfectly certain that all that has taken
place since that time must be referred to the
sixth day.
In the gfreat Carboniferous formation, whence
America derives so vast a proportion of her actual
and potential wealth, in the beds of coal which
have been formed from the vegetation of that
period, we find abundant evidence of the existence
of terrestrial animals. They have been described,
not only by European but by your own naturalists.
There are to be found numerous insects allied to
our cockroaches. There are to be found spiders
and scorpions of large size, the latter so similar
to existing scorpions that it requires the practised
eye of the naturalist to distinguish them. Inasmuch
as these animals can be proved to have been alive
in the Carboniferous epoch, it is perfectly clear
that, if the Miltonic account is to be accepted,
the huee mass of rocks extending- from the middle
of the Palaeozoic formations to the uppermost
members of the series, must belong to the day
which is termed by Milton the sixth. But, further,
it is expressly stated that aquatic animals took their
origin upon the fifth day, and not before ; hence,
all formations in which remains of aquatic animals
can be proved to exist, and which therefore testify
that such animals lived at the time when these for-
mations were in course of deposition, must have
24 LECTURES ON EVOLUTION. [lect. i.
been deposited during or since the period which
Milton speaks of as the fifth day. But there is
absolutely no fossiliferous formation in which the
remains of aquatic animals are absent. The oldest
fossils in the Silurian rocks are exuviae of marine
animals ; and if the view which is entertained by
Principal Dawson and Dr. Carpenter respecting the
nature of the Eozoon be well founded, aquatic ani-
mals existed at a period as far antecedent to the
deposition of the coal as the coal is from us ;
inasmuch as the Eozoon is met with in those
Laurentian strata which lie at the bottom of the
series of stratified rocks. Hence it follows, plainly
enough, that the whole series of stratified rocks, if
they are to be brought into harmony with Milton,
must be referred to the fifth and sixth days, and
that we cannot hope to find the slightest trace of
the products of the earlier days in the geological
record. When we consider these simple facts, we
see how absolutely futile are the attempts that have
been made to draw a parallel between the story
told by so much of the crust of the earth as is
known to us and the story which Milton tells.
The whole series of fossiliferous stratified rocks
must be referred to the last two days ; and neither
the Carboniferous, nor any other, formation can
afford evidence of the work of the third day.
Not only is there this objection to any attempt
i.ECT. I.] THE MILTON IC HYPOTHESIS. 25
to establish a harmony between the Miltonic ac-
count and the facts recorded in the fossihferous
rocks, but there is a further difficulty. According-
to the Miltonic account, the order in which animals
should have made their appearance in the stratified
rocks would be this : Fishes, including the great
whales, and birds ; after them, all varieties of ter-
restrial animals except birds. Nothing could be
further from the facts as we find them ; we know
of not the slightest evidence of the existence of
birds before the Jurassic, or perhaps the Triassic,
formation ; while terrestrial animals, as we have
just seen, occur in the Carboniferous rocks.
If there were any harmony between the Miltonic
account and the circumstantial evidence, we ought
to have abundant evidence of the existence of birds
in the Carboniferous, the Devonian, and the Silurian
rocks. I need hardly say that this is not the
case, and that not a trace of birds makes its
appearance until the far later period which I have
mentioned.
And again, if it be true that all varieties of fishes
and the great whales, and the like, made their
appearance on the fifth day, we ought to find the
remains of these animals in the older rocks — in
those which were deposited before the Carboni-
ferous epoch. Fishes we do find, in considerable
number and variety ; but the great whales are
z6 LECTURES ON EVOLUTION. [lect. i.
absent, and the fishes are not such as now live.
Not one soHtary species of fish now in existence
is to be found in the Devonian or Silurian
formations^ Hence we are introduced afresh to the
dilemma which I have already placed before you :
either the animals which came into existence on
the fifth day were not such as those which are
found at present, are not the direct and immediate
ancestors of those which now exist ; in which case
either fresh creations of which nothing is said ; or
a process of evolution must have occurred ; or else
the whole story must be given up, as not only
devoid of any circumstantial evidence, but contrary
to such evidence as exists.
I placed before you in a few words, some little
time ago, a statement of the sum and substance
of Milton's hypothesis. Let me now try to state
as briefly, the effect of the circumstantial evidence
bearing upon the past history of the earth which
is furnished, without the possibiHty of mistake, with
no chance of error as to its chief features, by the
stratified rocks. What we find is, that the great
series of formations represents a period of time
of which our human chronologies hardly afford us
a unit of measure. I will not pretend to say how
we ought to estimate this time, in millions or in
billions of years. For my purpose, the determina-
tion of its absolute duration is wholly unessential.
LECT. I.] THE MILTONIC HYPOTHESIS. 27
But that the time was enormous there can be no
question.
It results from the simplest methods of inter-
pretation, that leaving out of view certain patches
of metamorphosed rocks, and certain volcanic pro-
ducts, all that is now dry land has once been at the
bottom of the waters. It is perfectly certain that,
at a comparatively recent period of the world's
history — the Cretaceous epoch — none of the great
physical features which at present mark the surface
of the globe existed. It is certain that the Rocky
Mountains were not. It is certain that the Hima-
laya Mountains were not. It is certain that the
Alps and the Pyrenees had no existence. The
evidence is of the plainest possible character, and
is simply this : — We find raised up on the flanks
of these mountains, elevated by the forces of up-
heaval which have given rise to them, masses of
Cretaceous rock which formed the bottom of the
sea before those mountains existed. It is therefore
clear that the elevatory forces which gave rise to
the mountains operated subsequently to the Cre-
taceous epoch ; and that the mountains themselves
are largely made up of the materials deposited in
the sea which once occupied their place. As we
go back in time, we meet with constant alternations
of sea and land, of estuary and open ocean ; and,
in correspondence with these alternations, we
28 LECTURES ON EVOLUTION. [lect. i.
observe the changes in the fauna and flora to
which I have referred.
But the inspection of these changes give us no
right to beUeve that there has been any discon-
tinuity in natural processes. There is no trace of
general cataclysms, of universal deluges, or sud-
den destructions of a whole fauna or flora. The
appearances which were formerly interpreted in
that way have all been shown to be delusive, as
our knowledge has increased and as the blanks
which formerly appeared to exist between the
different formations have been filled up. That
there is no absolute break between formation
and formation, that there has been no sudden
disappearance of all the forms of life and replace-
ment of them by others, but that changes have
gone on slowly and gradually, that one type has
died out and another has taken its place, and that
thus, by insensible degrees, one fauna has been
replaced by another, are conclusions strengthened,
by constantly increasing evidence. So that within
the whole of the immense period indicated by the
fosslliferous stratified rocks, there is assuredly not
the slightest proof of any break in the uniformity
of Nature's operations, no indication that events
have followed other than a clear and orderly
sequence.
That, I say, is the natural and obvious teaching
LECT. I.] THE HYPOTHESIS OF EVOLUTION. 29
of the circumstantial evidence contained in the
stratified rocks. I leave you to consider how far,
by any ingenuity of interpretation, by any stretching
of the meaning of language, it can be brought into
harmony with the Miltonic hypothesis.
There remains the third hypothesis, that of
which I have spoken as the hypothesis of evolu-
tion ; and I purpose that, in lectures to come, we
should discuss it as carefully as we have con-
sidered the other two hypotheses. I need not say
that it is quite hopeless to look for testimonial
evidence of evolution. The very nature of the
case precludes the possibility of such evidence, for
the human race can no more be expected to testify
to its own origin, than a child can be tendered as
a witness of its own birth. Our sole inquiry is,
what foundation circumstantial evidence lends to
the hypothesis, or whether it lends none, or whether
it controverts the hypothesis. I shall deal with the
matter entirely as a question of history. I shall
not indulge in the discussion of any speculative pro-
babilities. I shall not attempt to show that Nature
is unintelligible unless we adopt some such hypo-
thesis. For anything I know about the matter, it
may be the way of Nature to be unintelligible ; she
is often puzzling, and I have no reason to suppose
that she is bound to fit herself to our notions.
I shall place before you three kinds of evidence
30 LECTURES ON EVOLUTION. [lect. .
entirely based upon what is known of the forms
of animal life which are contained in the series
of stratified rocks. I shall endeavour to show you
that there is one kind of evidence which is neutral,
which neither helps evolution nor is inconsistent
with it. I shall then bring forward a second kind
of evidence which indicates a strong probability in
favour of evolution, but does not prove it ; and,
lastly, 1 shall adduce a third kind of evidence
which, being as complete as any CA^idence which
we can hope to obtain upon such a subject, and
being wholly and strikingly in favour of evolution,
may fairly be called demonstrative evidence of its
occurrence.
LECTURE II.
THE HYPOTHESIS OF EVOLUTION.
THE NEUTRAL AND THE FAVOURABLE EVIDENCE.
In the preceding lecture I pointed out that there
are three hypotheses which may be entertained,
and which have been entertained, respecting the
past history of hfe upon the globe. According to
the first of these hypotheses, living beings, such as
now exist, have existed from all eternity upon this
earth. We tested that hypothesis by the circum-
stantial evidence, as I called it, which is furnished
by the fossil remains contained in the earth's crust,
and we found that it was obviously untenable. I
then proceeded to consider the second hypothesis,
which I termed the Miltonic hypothesis, not because
it is of any particular consequence to me whether
John Milton seriously entertained it or not, but
because it is stated in a clear and unmistakable
manner in his great poem. I pointed out to you'
that the evidence at our command as completely
32 LECTURES ON EVOLUTION. [lect. ii.
and fully negatives that hypothesis as it did the
preceding one. And I confess that I had too much
respect for your intelligence to think it necessary
to add that the negation was equally clear and
ec^ually valid, whatever the source from which that
hypothesis might be derived, or whatever the
authority by which it might be supported. I
further stated that, according to the third hypo-
thesis, or that of evolution, the existing state of
things is the last term of a long series of states,
which, when traced back, would be found to show
no interruption and no breach in the continuity of
natural causation. I propose, in the present, and the
following lecture, to test this hypothesis rigorously
by the evidence at command, and to inquire how
far that evidence can be said to be indifferent to
it, hov/ far it can be said to be favourable to
it, and, finally, how far it can be said to be
demonstrative.
From almost the origin of the discussions about
the existing condition of the animal and vegetable
worlds and the causes which have determined that
condition, an argument has been put forward as an
objection to evolution, which we shall have to con-
sider very seriously. It is an argument which was
first clearly stated by Cuvier In his criticism of the
doctrines propounded by his great contemporary,
Lamarck. The French expedition to Egypt had
LF.CT. II.] PERSISTENT TYPES. 33
called the attention of learned men to the wonderful
store of antiquities in that country, and there had
been brought back to France numerous mummified
corpses of the animals which the ancient Egyptians
revered and preserved, and which, at a reasonable
computation, must have lived not less than three
or four thousand years before the time at which
they were thus brought to light. Cuvier endea-
voured to test the hypothesis that animals have
undergone gradual and progressive modifications of
structure, by comparing the skeletons and such other
parts of the mummies as were in a fitting state
of preservation, with the corresponding parts of the
representatives of the same species now living in
Egypt. He arrived at the conviction that no
appreciable change had taken place in these animals
in the course of this considerable lapse of time,
and the justice of his conclusion is not disputed.
It is obvious that, if it can be proved that animals
have endured, without undergoing any demonstrable
change of structure, for so long a period as four
thousand years, no form of the hypothesis of evolu-
tion which assumes that animals undergo a constant
and necessary progressive change can be tenable ;
unless, indeed, it be further assumed that four
thousand years is too short a time for the produc-
tion of a change sufficiently great to be detected.
But it is no less plain that if the process of
34 LECTURES ON EVOLUTION. [lect. ii.
evolution of animals is not independent of sur-
rounding conditions ; if it may be indefinitely
hastened or retarded by variations in these condi-
tions ; or if evolution is simply a process of accom-
modation to varying conditions; the argument against
the hypothesis of evolution based on the unchanged
character of the Egyptian fauna is worthless. For
the monuments which are coeval with the mummies
testify as strongly to the absence of change in the
physical geography and the general conditions of
the land of Egypt, for the time in question, as
the mummies do to the unvarying characters of its
living population.
The progress of research since Cuvier's time has
supplied far more striking examples of the long
duration of specific forms of life than those which
are furnished by the mummified Ibises and Croco-
diles of Egypt. A remarkable case is to be found
in your own country, in the neighbourhood of the
falls of Niagara. In the immediate vicinity of the
whirlpool, and again upon Goat Island, in the
superficial deposits which cover the surface of
the rocky subsoil in those regions, there are found re-
mains of animals in perfect preservation, and among
them, shells belonging to exactly the same species
as thsoe which at present inhabit the still waters
of Lake Erie. It is evident, from the structure
of the country, that these animal remains were
LECT. 11.] PERSISTENT TYPES. 35
deposited in the beds in which they occur at a
time when the lake extended over the region in
which they are found. This involves the conclusion
that they lived and died before the falls had cut
their way back through the gorge of Niagara; and,
indeed, it has been determined that, when these
animals lived, the falls of Niagara must have been
at least six miles further down the river than they
are at present. Many computations have been
made of the rate at which the falls are thus cutting
their way back. Those computations have varied
greatly, but I believe I am speaking within the
bounds of prudence, if I assume that the falls of
Niagara have not retreated at a greater pace than
about a foot a year. Six miles, speaking roughly,
are 30,000 feet ; 30,000 feet, at a foot a year, gives
30,000 years ; and thus we are fairly justified in
concluding that no less a period than this has
passed since the shell-fish, whose remains are left
in the beds to which I have referred, were living
creatures.
But there is still stronger evidence of the
long duration of certain types. I have already
stated that, as we work our way through the
great series of the Tertiary formations, we find
many species of animals identical with those which
live at the present day, diminishing in numbers, it
is true, but still existing, in a certain proportion,
36 LECTURES ON EVOLUTION. [lect. ii.
in the oldest of the Tertiary rocks. Furthermore,
when we examine the rocks of the Cretaceous
epoch, we find the remains of some animals which
the closest scrutiny cannot show to be, in any
important respect, different from those which live
at the present time. That is the case with one
of the cretaceous lamp-shells {Tei^ebratula), which
has continued to exist unchanged, or with insigni-
ficant variations, down to the present day. Such
is the case with the Globigeidiue, the skeletons of
which, aggregated together, form a large proportion
of our Encrlish chalk. Those Globizerince can be
traced down to the GlobizeiniicB which live at the
surface of the present great oceans, and the remains
of which, falling to the bottom of the sea, give
rise to a chalky mud. Hence it must be admitted
that certain existing species of animals show no dis-
tinct sign of modification, or transformation, in the
course of a lapse of time as great as that which
carries us back to the Cretaceous period ; and
which, whatever its absolute measure, is certainly
vastly greater than thirty thousand years.
There are groups of species so closely allied
together that it needs the eye of a naturalist to
distinguish them one from another. If we disregard
the small differences which separate these forms
and consider all the species of such groups as
modifications of one type, we shall find that, even
LECT. II.] PERSISTENT TYPF.S. 37
among the higher animals, some types have had a
marvellous duration. In the chalk, for example,
there is found a fish belonging to the highest and
the most differentiated group of osseous fishes, which
goes by the name of Beryx. The remains of that
fish are among the most beautiful and well pre-
served of the fossils found in our English chalk.
It can be studied anatomically, so far as the hard
parts are concerned, almost as well as if it were a
recent fish. But the genus Beryx is represented, at
the present day, by very closely allied species which
are living in the Pacific and Atlantic Oceans. We
may go still farther back. I have already referred to
the fact that the Carboniferous formations, in Europe
and in America, contain the remains of scorpions in
an admirable state of preservation, and that those
scorpions are hardly distinguishable from such as
now live. I do not mean to say that they are not
different, but close scrutiny is needed in order to
distinguish them from modern scorpions.
More than this. At the very bottom of the
Silurian series, in beds which are by some authori-
ties referred to the Cambrian formation, where the
signs of life begin to fail us — even there, among
the few and scanty animal remains which are dis-
coverable, we find species of molluscous animals
which arc so closely allied to existing forms that,
at one time, they were grouped under the same
38 LECTURES ON EVOLUTION. [lect. ii.
generic name. I refer to the well-known Lingula
of the Lingula flags, lately, in consequence of some
slight differences, placed in the new genus Lin-
gulella. Practically, it belongs to the same great
generic group as the Lingula, which is to be found
at the present day upon your own shores and those
of many other parts of the world.
The same truth is exemplified if we turn to
certain great periods of the earth's history — as, for
example, the Mesozoic epoch. There are groups of
reptiles, such as the LchthyosauiHa and the Plesio-
sauria, which appear shortly after the commencement
of this epoch, and they occur in vast numbers.
They disappear with the chalk and, throughout
the whole of the great series of Mesozoic rocks,
they present no such modifications as can safely
be considered evidence of progressive modification.
Facts of this kind are undoubtedly fatal to any
form of the doctrine of evolution which postulates
the supposition that there is an intrinsic necessity,
on the part of animal forms which have once come
into existence, to undergo continual modification ;
and they are as distinctly opposed to any view
which involves the belief, that such modification as
may occur, must take place, at the same rate, in all
the different types of animal or vegetable life. The
facts, as I have placed them before you, obviously
directly contradict any form of the hypothesis of
LECT. II.] VARIATION AND CONDITIONS. 39
evolution which stands in need of these two pos-
tulates.
But, one great service that has been rendered
by Mr. Darwin to the doctrine of evolution in
general is this : he has shown that there are two
chief factors in the process of evolution :* one of
them is the tendency to vary, the existence of
which in all living forms may be proved by obser-
vation ; the other is the influence of surrounding
conditions upon what I may call the parent form and
the variations which are thus evolved from it. The
cause of the production of variations is a matter
not at all properly understood at present. Whether
variation depends upon some intricate machinery
— if I may use the phrase — of the living organism
itself, or whether it arises through the influence of
conditions upon that form, is not certain, and the
question may, for the present, be left open. But
the important point is that, granting the existence
of the tendency to the production of variations ;
then, whether the variations which are produced
shall survive and supplant the parent, or whether
the parent form shall survive and supplant the
variations, is a matter which depends entirely on
those conditions which give rise to the struggle for
existence. If the surrounding conditions are such
that the parent form is more competent to deal
with them and flourish in them, than the derived
40 LECTURES ON EVOLUTION. [lect. ii.
forms, then, in the struggle for existence, the parent
form will maintain itself and the derived forms will
be exterminated. But if, on the contrary, the con-
ditions are such as to be more favourable to a
derived than to the parent form, the parent form
will be extirpated and the derived form will take
its place. In the first case, there will be no pro-
gression, no change of structure, through any ima-
ginable series of ages ; in the second place, there
will be modification and change of form.
Thus the existence of these persistent types, as
I have termed them, is no real obstacle in the way
of the theory of evolution. Take the case of the
scorpions to which I have just referred. No doubt,
since the Carboniferous epoch, conditions have
always obtained, such as existed when the scorpions
of that epoch flourished ; conditions in which
scorpions find themselves better off, more competent
to deal with the difficulties in their way, than any
variation from the scorpion type which they may
have produced ; and, for that reason, the scorpion
type has persisted, and has not been supplanted
by any other form. And there is no reason, in the
nature of things, why, as long as this world exists,
if there be conditions more favourable to scorpions
than to any variation which may arise from them,
these forms of life should not persist.
Therefore, the stock objection to the hypothesis
LECT. II.] INDIFFERENT EVIDENCE. 41
of evolution, based on the long duration of certain
animal and vegetable types, is no objection at all.
The facts of this character — and they are numerous
—belong to that class of evidence which I have
called indifferent. That is to say, they may afford
no direct support to the doctrine of evolution, but
they are capable of being interpreted in perfect
consistency with it.
There is another order of facts belonging to the
class of negative or indifferent evidence. The great
group of Lizards, which abound in the present
world, extends through the whole series of forma-
tions as far back as the Permian, or latest Palaeozoic,
epoch. These Permian lizards differ astonishingly
litde from the lizards which exist at the present
day. Comparing the amount of the differences
between them and modern lizards, with the pro-
digious lapse of time between the Permian epoch
and the present age, it may be said that the amount
of change is insignificant. But, when we carry our
researches farther back in time, we find no trace
of lizards, nor of any true reptile whatever, in the
whole mass of formations beneath the Permian.
Now, it is perfectly clear that if our palaeonto-
logical collections are to be taken, even approxi-
mately, as an adequate representation of all the
forms of animals and plants that have ever lived;
and if the record furnished by the known series
3
42 LECTURES ON EVOLUTION. [lect. ii.
of beds of stratified rock, covers the whole series
of events which constitute the history of hfe on the
globe, such a fact as this directly contravenes the
hypothesis of evolution ; because this hypothesis
postulates that the existence of every form must
have been preceded by that of some form little
different from it. Here, however, we have to take
into consideration that important truth so well
insisted upon by Lyell and by Darwin — the im-
perfection of the geological record. It can be
demonstrated that the geological record must be
incomplete, that it can only preserve remains found
in certain favourable localities and under particular
conditions ; that it must be destroyed by processes
of denudation, and obliterated by processes of
metamorphosis. Beds of rock of any thickness,
crammed full of organic remains, may yet, either
by the percolation of water through them, or by
the influence of subterranean heat, lose all trace
of these remains, and present the appearance of
beds of rock formed under conditions in which
living forms were absent. Such metamorphic rocks
occur in formations of all ages ; and, in various cases,
there are very good grounds for the belief that
they have contained organic remains, and that those
remains have been absolutely obliterated.
I insist upon the defects of the geological record
the more because those who have not attended to
LECT. II.] IMPERFECTION OF THE RECORD. 43
these matters are apt to say, " It is all very well,
but, when you get into a difficulty with your theory
of evolution, you appeal to the incompleteness and
the imperfection of the geological record ; " and I
want to make it perfectly clear to you that this
imperfection is a great fact, which must be taken
into account in all our speculations, or we shall
constantly be going wrong.
You see the singular series of footmarks,
drawn of its natural size in the large diagram
hanging up here (Fig. 2), which I owe to the kind-
ness of my friend Professor Marsh, with whom I had
the opportunity recently of visiting the precise locality
in Massachusetts in which these tracks occur. I am,
Fig. 2. — Tracks of Brontozoum.
therefore, able to give you my own testimony, if
needed, that the diagram accurately represents what
we saw. The valley of the Connecticut is classical
ground for the geologist. It contains great beds of
san'^-stone, covering many square miles, which have
evicently formed a part of an ancient sea-shore, or,
it may be, lake-shore. For a certain period of time
aftc- their deposition, these beds have remained
44 LECTURES ON EVOLUTION [lect. ii.
sufficiently soft to receive the impressions of the
feet of whatever animals walked over them, and to
preserve them afterwards, in exactly the same way
as such impressions are at this hour preserved on
the shores of the Bay of Fundy and elsewhere.
The diagram represents the track of some gigantic
animal, which walked on its hind legs. You see
the series of marks made alternately by the right
and by the left foot ; so that, from one impression
to the other of the three-toed foot on the same side,
is one stride, and that stride, as we measured it,
is six feet nine inches. I leave you, therefore, to
form an impression of the magnitude of the creature
which, as it walked along the ancient shore, made
these impressions.
Of such impressions there are untold thousands
upon these sandstones. Fifty or sixty different
kinds have been discovered, and they cover vast
areas. But, up to this present time, not a bone,
not a fragment, of any one of the animals which
left these great footmarks has been found ; in fact,
the only animal remains which have been met with
in all these deposits, from the time of their dis-
covery to the present day — though they have been
carefully hunted over — is a fragmentary skel'^::;'con
of one of the smaller forms. What has becon'ie of
the bones of all these animals ? You see we are
not dealing with little creatures, but with aniinals
LECT. II.] IMPERFECTION OF THE RECORD. 45
that make a step of six feet nine inches ; and their
remains must have been left somewhere. The pro-
bability is, that they been dissolved away, and
absolutely lost.
I have had occasion to work out the nature of
fossil remains, of which there was nothing- left
except casts of the bones, the solid material of the
skeleton having- been dissolved out by percolating
water. It was a chance, in this case, that the sand-
stone happened to be of such a constitution as to
set, and to allow the bones to be afterward dis-
solved out, leaving cavities of the exact shape of
the bones. Had that constitution been other than
what it was, the bones would have been dissolved,
the layers of sandstone would have fallen together
into one mass, and not the slightest indication that
the animal had existed would have been dis-
foverable.
I know of no more striking evidence than these
facts afford, of the caution which should be used
in drawing the conclusion, from the absence of
organic remains in a deposit, that animals or plants
did not exist at the time it was formed. I believe
tha, with a right understanding of the doctrine of
evolution on the one hand, and a just estimation
of -he importance of the imperfection of the geo-
logical record on the other, all difficulty is removed
fro n the kind of evidence to which I have
46 LECTURES ON EVOLUTION. [lect, ii.
adverted ; and that we are justified in believing that
all such cases are examples of what I have desig-
nated negative or indifferent evidence — that is to
say, they in no way directly advance the hypothesis
of evolution, but they are not to be regarded as
obstacles in the way of our belief in that doctrine.
I now pass on to the consideration of those
cases which, for reasons which I will point out to
you by and by, are not to be regarded as demon-
strative of the truth of evolution, but which are
such as must exist if evolution be true, and which
therefore are, upon the whole, evidence in favour
of the doctrine. If the doctrine of evolution be
true, it follows, that, however diverse the different
groups of animals and of plants may be, they must
all, at one time or other, have been connected by gra-
dational forms ; so that, from the highest animals,
whatever they may be, down to the lowest speck
of protoplasmic matter in which life can be mani-
fested, a series of gradations, leading from one end
of the series to the other, either exists or has
existed. Undoubtedly that is a necessary postulate
of the doctrine of evolution. But when we look
upon living Nature as it is, we find a totalb --dif-
ferent state of things. We find that animals ..nd
plants fall into groups, the different memberr^ of
which are pretty closely allied together, but which
are separated by definite, larger or smaller, breaks
LECT. II.] INTERCALARY TYPES. 47
from other groups. In other words, no intermediate
forms which bridge over these gaps or intervals
are, at present, to be met with.
To illustrate what I mean : Let me call your
attention to those vertebrate animals which are
most familiar to you, such as mammals, birds, and
reptiles. At the present day, these groups of
animals are perfectly well defined from one another.
We know of no animal now living which, in any
sense, is intermediate between the mammal and the
bird, or between the bird and the reptile ; but, on
the contrary, there are many very distinct anatomical
peculiarities, well-defined marks, by which the mam-
mal is separated from the bird, and the bird from
the reptile. The distinctions are obvious and
striking if you compare the definitions of these
great groups as they now exist.
The same may be said of many of the subordi-
nate groups, or orders, into which these great classes
are divided. At the present time, for example, there
are numerous forms of non-ruminant pachyderms,
or what we may call broadly, the pig tribe, and
many varieties of ruminants. These latter have
their definite characteristics, and the former have
their distinguishing peculiarities. But there is
nothing that fills up the gap between the ruminants
and the pig tribe. The two are distinct. Such
also is the case in respect of the minor groups of
LECTURES ON EVOLUTION. [lect. il
the class of reptiles. The existing fauna shows us
crocodiles, lizards, snakes, and tortoises ; but no
connecting link between the crocodile and lizard,
nor between the lizard and snake, nor between
the snake and the crocodile, nor between any two
of these groups. They are separated by absolute
breaks. If, then, it could be shown that this state
of things had always existed, the fact would be
fatal to the doctrine of evolution. If the inter-
mediate gradations, which the doctrine of evolution
requires to have existed between these groups, are
not to be found anywhere in the records of the past
history of the globe, their absence is a strong and
weighty negative argument against evolution ; while,
on the other hand, if such intermediate forms are
to be found, that is so much to the good of evolu-
tion ; although, for reasons which I will lay before
you by and by, we must be cautious in our estimate
of the evidential cogency of facts of this kind.
It is a very remarkable circumstance that, from
the commencement of the serious study of fossil
remains ; in fact, from the time when Cuvier beean
his brilliant researches upon those found in the
quarries of Montmartre, palaeontology has shown
iwhat she was going to do in this matter, and what
kind of evidence it lay in her power to produce.
I said just now that, in the existing Fauna, the
group of pig-like animals and the group of rumi-
J.ECT. II.] INTERCALARY TYPES. 45
nants are entirely distinct ; but one of the first of
Cuvier's discoveries was an animal which he called
the Ajioplothe^Hum, and which proved to be, in
a great many important respects, intermediate in
character between the pigs, on the one hand, and
the ruminants on the other. Thus research into
the history of the past did, to a certain extent, tend
to fill up the breach between the group of rumi-
nants and the group of pigs. Another remarkable
animal restored by the great French palaeontologist,
the PalcEotherium, similarly tended to connect
together animals to all appearance so different as
the rhinoceros, the horse, and the tapir. Subse-
quent research has brought to light multitudes of
facts of the same order ; and, at the present day,
the investigations of such anatomists as Rutlmeyer
and Gaudry have tended to fill up, more and more,
the gaps in our existing series of mammals, and to
connect groups formerly thought to be distinct.
But I think It may have an especial interest if,
instead of dealing with these examples, which would
require a great deal of tedious osteological detail,
I take the case of birds and reptiles ; groups which,
at the present day, are so clearly distinguished from
one another that there are perhaps no classes of
animals which, In popular apprehension, are more
completely separated. Existing birds, as you are
aware, are covered with feathers ; their anterior
50 LECTURES ON EVOLUTION. [lect. ii.
extremities, specially and peculiarly modified, are
converted into wings, by the aid of which most of
them are able to fly ; they walk upright upon two
legs ; and these limbs, when they are considered
anatomically, present a great number of exceedingly
remarkable peculiarities, to which I may have
occasion to advert incidentally as I go on, and
which are not met with, even approximately, in
any existing forms of reptiles. On the other hand,
existing reptiles have no feathers. They may have
naked skins, or be covered with horny scales, or
bony plates, or with both. They possess no wings ;
they neither fly by means of their fore-limbs, nor
habitually walk upright upon their hind-limbs ; and
the bones of their legs present no such modifications
as we find in birds. It is impossible to imagine
any two groups more definitely and distinctly sepa-
rated, notwithstanding certain characters which they
possess in common.
As we trace the history of birds back in time, we
find their remains, sometimes in great abundance,
throughout the whole extent of the tertiary rocks I
but, so far as our present knowledge goes, the birds
of the tertiary rocks retain the same essential cha-
racters as the birds of the present day. In other
words, the tertiary birds come within the definition
of the class constituted by existing birds, and are as
much separated from reptiles as existing birds are.
LECT. 11.] BIRDS WITH TEETH. 51
Not very long ago no remains of birds had been
found below the tertiary rocks, and I am not sure
but that some persons were prepared to demonstrate
that they could not have existed at an earlier period.
But, in the course of the last few years, such remains
have been discovered in England ; though, unfortu-
nately, in so imperfect and fragmentary a condition,
that it is Impossible to say whether they differed
from existing birds in any essential character or not.
In your country the development of the cretaceous
series of rocks is enormous ; the conditions under
which the later cretaceous strata have been de-
posited are highly favourable to the preservation of
organic remains ; and the researches, full of labour .
and risk, which have been carried on by Professor
Marsh in these cretaceous rocks of Western America,
have rewarded him with the discovery of forms of
birds of which we had hitherto no conception. By
his kindness, I am enabled to place before you a
restoration of one of these extraordinary birds, every
part of which can be thoroughly justified by the more
or less complete skeletons, in a very perfect state of
preservation, which he has discovered. This Hes-
perornis (Fig. 3), which measured between five and
six feet in length, is astonishingly like our existing
divers or grebes in a great many respects ; so like
them indeed that, had the skeleton of Hesperornis
been found in a museum without its skull, it
52
LECTURES ON EVOLUTION. [lect. ii.
probably would have been placed in the same group
Fig. 3. — Hesperornis regalis (Marsh).
of birds as the divers and grebes of the present day.'
^ The absence of any keel on the breast-bone and some other
osteological pecuHarities, observed by Professor Marsh, however,
suggest that Hesperornis may be a modification of a less specialised
group of birds than that to which these existing aquatic birds belong.
LECT. II.]
HESPERORNIS REGALIS.
53
Fig. 4. — HESPERORNIS regalis (Marsh).
(Side and upper views of half the lower jaw ; side and end views of a vertebra
and a separate tooth. )
54 LECTURES ON EVOLUTION. [lect. ii.
But Hesperornis differs from all existing birds, and
so far resembles reptiles, in one important particular
— it is provided with teeth. The long jaws are
armed with teeth which have curved crowns and
thick roots (Fig. 4), and are not set in distinct
sockets, but are lodged in a groove. In possessing
true teeth, the Hesperornis differs from every ex-
isting bird, and from every bird yet discovered in
the tertiary formations, the tooth-like serrations of
the jaws in the Odoiitopieryx of the London clay
being mere processes of the bony substance of the
jaws, and not teeth in the proper sense of the word.
In view of the characteristics of this bird we are
therefore obliged to modify the definitions of the
classes of birds and reptiles. Before the discovery
of Hesperornis, the definition of the class Aves
based upon our knowledge of existing birds, might
have been extended to all birds ; it might have been
said that the absence of teeth was characteristic of
the class of birds ; but the discovery of an animal
which, in every part of its skeleton, closely agrees
with existing birds, and yet possesses teeth, shows
that there were ancient birds which, in respect of
possessing teeth, approached reptiles more nearly
than any existing bird does, and, to that extent,
diminishes the hiatus between the two classes.
The same formation has yielded another bird
IcJUJiyorfiis (Fig. 5), which also possesses teeth ;
LECT. II.]
ICHTHYORNIS DISPAR.
55
I'lG. 5. — ICHTHYORNIS DiSPAR (Maisll).
(Side and upper views of half the lower jaw ; and side and cntl views of a
vertebra. )
56 LECTURES ON EVOLUTION. [lect. ii.
but the teeth are situated in distinct sockets, while
those of Hesperornis are not so lodged. The lat-
ter also has such very small, almost rudimentary,
wings, that it must have been chiefly a swimmer
and a diver, like a Penguin ; while Ichthyornis has
strong wings and no doubt possessed corresponding
powers of flight. Ichthyornis also differed in the
fact that its vertebras have not the peculiar
characters of the vertebrae of existing and of all
known tertiary birds, but were concave at each
end. This discovery leads us to make a further
modification in the definition of the group of
birds, and to part with another of the characters
by which almost all existing birds are distinguished
from reptiles.
Apart from the few fragmentary remains from
the English greensand, to which I have referred,
the mesozoic rocks, older than those in which Hes-
perornis and Ichthyornis have been discovered
have afforded no certain evidence of birds, with
the remarkable exception of the Solenhofen slates.
These so-called slates are composed of a fine
grained calcareous mud which has hardened into
lithographic stone, and in which organic remains are
almost as well preserved as they would be if they
had been imbedded in so much plaster of Paris.
They have yielded the ArchcEopteryx, the existence
of which was first made known by the finding of
LECT. II.] ARCH.EOPTERYX. 57
a fossil feather, or rather of the impression of one.
It is wonderful enough that such a perishable thing
as a feather, and nothing more, should be disco-
vered ; yet, for a long time, nothing was known of
this bird except its feather. But, by and by a soli-
tary skeleton was discovered, which is now in the
British Museum. The skull of this solitary specimen
is unfortunately wanting, and it is therefore uncer-
tain whether the Archcvoptcryx possessed teeth or
not. But the remainder of the skeleton is so well
preserved as to leave no doubt respecting the main
features of the animal, which are very singular.
The feet are not only altogether bird-like, but have
the special characters of the feet of perching birds,
while the body had a clothing of true feathers.
Nevertheless, in some other respects, Archcsopteryx
is unlike a bird and like a reptile. There is a long
tail composed of many vertebrae. The structure of
the wing differs in some very remarkable respects
from that which it presents in a true bird. In the
latter, the end of the wing answers to the thumb
and two fingers of my hand ; but the metacarpal
bones, or those which answer to the bones of the
fingers which lie in the palm of the hand, are fused
together into one mass ; and the whole apparatus,
except the last joints of the thumb, is bound up
in a sheath of integument, while the edge of the
hand carries the principal quill-feathers. In the
58 LECTURES ON EVOLUTION. [lect. ii.
Archisopteryx, the upper-arm bone is like that of
a bird; and the two bones of the forearm are
more or less like those of a bird, but the fingers
are not bound together — they are free. What their
number may have been is uncertain ; but several,
if not all, of them were terminated by strong curved
claws, not like such as are sometimes found in
birds, but such as reptiles possess ; so that, in the
Archceopteryx, we have an animal which, to a certain
extent, occupies a midway place between a bird
and a reptile. It is a bird so far as its foot and
sundry other parts of its skeleton are concerned ;
it is essentially and thoroughly a bird by its
feathers ; but it is much more properly a reptile
in the fact that the region which represents the
hand has separate bones, with claws resembling
those which terminate the fore-limb of a reptile.
Moreover, it had a long reptile-like tail with a
fringe of feathers on each side ; while, in all true
birds hitherto known, the tail is relatively short,
and the vertebrae which constitute its skeleton are
generally peculiarly modified.
Like the Aiioplotheritwi and the Palcrotherunn,
therefore, Archceopteryx tends to fill up the interval
between groups which, in the existing world, are
widely separated, and to destroy the value of the
definitions of zoological groups based upon our
knowledge of existing forms. And such cases as
LECT. II.] LINEAR TYPES. 59
these constitute evidence in favour of evolution,
in so far as they prove that, in former periods of
the world's history, there were animals which over-
stepped the bounds of existing groups, and tended
to merge them into larger assemblages. They
show that animal organisation is more flexible than
our knowledge of recent forms might have led
us to believe ; and that many structural permuta-
tions and combinations, of which the present
world gives us no indication, may nevertheless have
existed.
But it by no means follows, because the Palcso-
therium has much in common with the Horse, on
the one hand, and with the Rhinoceros on the
other, that it is the intermediate form through
which Rhinoceroses have passed to become Horses,
or vice versa; on the contrary, any such supposition
would certainly be erroneous. Nor do I think it
likely that the transition from the reptile to the
bird has been effected by such a form as Archce-
opteryx. And it is convenient to distinguish
these intermediate forms between two groups,
which do not represent the actual passage from
the one group to the other, as intercalary types,
from those linear types which, more or less approxi-
mately, indicate the nature of the steps by which
the transition from one group to the other was
effected.
6o LECTURES ON EVOLUTION. [lect. ii.
I conceive that such linear forms, constituting a
series of natural gradations between the reptile and
the bird, and enabling us to understand the manner
in which the reptilian has been metamorphosed into
the bird type, are really to be found among a group
of ancient and extinct terrestrial reptiles known as
the Ornithoscelida. The remains of these animals
occur throughout the series of mesozoic formations,
from the Trias to the Chalk, and there are indica-
tions of their existence even in the later Palaeozoic
strata.
Most of these reptiles at present known are of
great size, some having attained a length of forty
feet or perhaps more. The majority resembled
lizards and crocodiles in their general form, and
many of them were, like crocodiles, protected by
an armour of heavy bony plates. But, in others,
the hind limbs elongate and the fore limbs shorten,
until their relative proportions approach those which
are observed in the short-winged, flightless, ostrich
tribe amonof birds.
The skull is relatively light, and in some cases
the jaws, though bearing teeth, are beak-like at
their extremities and appear to have been enveloped
in a horny sheath. In the part of the vertebral
column which lies between the haunch bones and
is called the sacrum, a number of vertebrae may
unite together into one whole, and in this respect
LECT. II.] LIMBS OF REPTILES AND BIRDS. 6i
as in some details of its structure, the sacrum of
these reptiles approaches that of birds.
But it is in the structure of the pelvis and of
the hind limb that some of these ancient reptiles pre-
sent the most remarkable approximation to birds,
and clearly indicate the way by which the most
specialized and characteristic features of the bird
may have been evolved from the corresponding
parts in the reptile.
In Fis^. 6, the pelvis and hind limbs of a croco-
dile, a three-toed bird, and an ornithoscelidan are
represented side by side ; and, for facility of com-
parison, in corresponding positions ; but it must be
recollected that, while the position of the bird's limb
is natural, that of the crocodile is not so. In the
bird, the thigh-bone lies close to the body, and the
metatarsal bones of the foot (ii., iii., iv., Fig. 6)
are, ordinarily, raised into a more or less vertical
position ; in the crocodile, the thigh-bone stands out
at an angle from the body, and the metatarsal
bones (i., ii., iii., iv.. Fig. 6) lie flat on the ground.
Hence, in the crocodile, the body usually lies squat
between the legs, while, in the bird, it is raised upon
tlie hind legs, as upon pillars.
In the crocodile, the pelvis is obviously composed
of three bones on each side : the ilium (//.), the
pubis (Pi).), and the ischium {Is). In the adult
bird there appears to be but one bone on each
62 LECTURES ON EVOLUTION. [lect. ir.
side. The examination of the pelvis of a chick,
however, shows that each half Is made up of three
bones, which answer to those which remain distinct
throughout life, in the crocodile. There is, there-
fore, a fundamental identity of plan In the con-
struction of the pelvis of both bird and reptile ;
though the differences in form, relative size, and
direction of the corresponding bones In the two
cases are very great.
But the most striking contrast between the two
lies in the bones of the leg and of that part of
the foot termed the tarsus, which follows upon the
leg. In the crocodile, the fibula (£) is relatively
large and Its lower end is complete. The tibia ( T)
has no marked crest at Its upper end, and its lower
end Is narrow and not pulley-shaped. There are
two rows of separate tarsal bones {As., Ca., &c.)
and four distinct metatarsal bones, with a rudiment
of a fifth.
In the bird, the fibula is small and Its lower end
diminishes to a point. The tibia has a strong crest
at its upper end and its lower extremity passes into
a broad pulley. There seem at first to be no tarsal
bones ; and only one bone, divided at the end into
three heads for the three toes which are attached
to It, appears in the place of the metatarsus.
In a young bird, however, the pulley-shaped
apparent end of the tibia is a distinct bone, which
LECT. II.] LIMBS OF REPTILES AND BIRDS.
63
represents the bones marked As., Ca., in the croco-
dile ; while the apparently single metatarsal bone
consists of three bones, which early unite with
one another and with an additional bone, which
represents the lower row of bones in the tarsus of
the crocodile.
Fig. 6. — Bird.
0RNITH03CELID.A.N.
CUOCODILE.
(The letters have the same signification in all the figures. //., Ilium ;
fl, anterior end ; l>, posterior end; /s., ischium ; Fd., pubis; T, tibia;
jF, fibula; /Is., astragalus; Ca., calcaneum ; 1, distal portion of the
tarsus ; i., ii., iii., iv., metatarsal bones.)
In other words, it can be shown by the study of
development that the bird's pelvis and hind limb
64 LECTURES ON EVOLUTION. [lect. ii.
are simply extreme modifications of the same fun-
damental plan as that upon which these parts are
modelled in reptiles.
On comparing" the pelvis and hind limb of the
ornithoscelidan with that of the crocodile, on the one
side, and that of the bird, on the other (Fig. 6), it
is obvious that it represents a middle term between
the two. The pelvic bones approach the form of
those of the birds, and the direction of the pubis
and ischium is nearly that which is characteristic of
birds ; the thigh bone, from the direction of its
head, must have lain close to the body ; the tibia
has a great crest ; and, immovably fitted on to its
lower end, there is a pulley-shaped bone, like that
of the bird, but remaining distinct. The lower end
of the fibula is much more slender, proportionally,
than in the crocodile. The metatarsal bones have
such a form that they fit together immovably,
though they do not enter into bony union ; the third
toe is, as in the bird, longest and strongest. In
fact, the ornithoscelidan limb is comparable to that
of an unhatched chick.
Taking all these facts together, it is obvious that
the view, which was entertained by Mantell and the
probability of which was demonstrated by your
own distinguished anatomist, Leidy, while much
additional evidence in the same direction has been
furnished by Professor Cope, that some of these
LECT. 11.]
BIPEDAL REPTILES.
65
animals may have walked upon their hind legs, as
birds do, acquires great weight. In fact, there can
be no reasonable doubt that one of the smaller
forms of the Ornithoscelida, Compsognathus, the
almost entire skeleton of which has been discovered
in the Solenhofen slates, was a bipedal animal.
The parts of this skeleton are somewhat twisted
out of their natural relations, but the accompanying
Fig. 7. — Restoration of Compsognatuus longipes.
figure gives a just view of the general form of
Compsognathus and of the proportions of its limbs ;
which, in some respects, are more completely bird-
like than those of other Ornithoscelida.
We have had to stretch the definition of the
class of birds so as to include birds with teeth
4
66 LECTURES ON EVOLUTION. [lect. n.
and birds with paw-like fore-limbs and long tails.
There is no evidence that Compsognathus possessed
feathers ; but, if it did, it would be hard indeed to
say whether it should be called a reptilian bird or
an avian reptile.
As Compsognathus walked upon its hind legs, it
must have made tracks like those of birds. And
as the structure of the limbs of several of the
gigantic Ornitkoscelida, such as Iguandon, leads
to the conclusion that they also may have constantly,
or occasionally, ass umed the same attitude, a peculiar
interest attaches to the fact that, in the Wealden
strata of England, there are to be found gigantic
footsteps, arranged in order like those of the Bron-
tozoum, and which there can be no reasonable doubt
were made by some of the Ornithoscelida, the re-
mains of which are found in the same rocks. And,
knowing that reptiles that walked upon their hind
legs and shared many of the anatomical characters of
birds did once exist, it becomes a very important
question whether the tracks in the Trias of Massa-
chusetts, to which I referred some time ago, and
which formerly used to be unhesitatingly ascribed
to birds, may not all have been made by Orni-
thoscelidan reptiles ; and whether, if we could obtain
the skeletons of the animals which made these
tracks, we should not find in them the actual steps
of the evolutional process by which reptiles gave
rise to birds.
LECT. II.] FLYING REPTILES. 67
The evidential value of the facts I have brought
forward in this Lecture must be neither over nor
under estimated. It is not historical proof of the
occurrence of the evolution of birds from reptiles,
for we have no safe eround for assuminsf that true
birds had not made their appearance at the com-
mencement of the Mesozoic epoch. It is, in fact,
quite possible that all these more or less avi-form
reptiles of the Mesozoic epoch are not terms in
the series of progression from birds to reptiles at
all, but simply the more or less modified descendants
of Palaeozoic forms through which that transition
was actually effected.
We are not in a position to say that the known
OrnitJioscelida are intermediate in the order of their
appearance on the earth between reptiles and birds.
All that can be said is that, if independent evidence
of the actual occurrence of evolution is producible,
then these intercalary forms remove every difficulty
in the way of understanding what the actual steps of
the process, in the case of birds, may have been.
That intercalary forms should have existed in
ancient times is a necessary consequence of the
truth of the hypothesis of evolution ; and, hence,
the evidence I have laid before you in proof of
the existence of such forms, is, so far as it goes,
in favour of that hypothesis.
There is another series of extinct reptiles, which
may be said to be intercalary between reptiles and
68
LECTURES ON EVOLUTION. [lect. ii.
birds, in so far as they combine some of the cha-
racters of both these groups ; and, which, as they
possessed the power of flight, may seem, at first
Fig. 8.— Pterodactylus Spectabilis (Von Meyer).
sight, to be nearer representatives of the forms by
which the transition from the reptile to the bird
was effected, than the Ornithoscdida.
LECT. II.] FLYING REPTILES. 69
These are the Pierosauria, or Pterodactyles, the
remains of which are met with throughout the series
of Mesozoic rocks, from the lias to the chalk, and
some of which attained a great size, their wings
having a span of eighteen or twenty feet. These
animals, in the form and proportions of the head
and neck relatively to the body, and in the fact that
the ends of the jaws were often, If not always, more
or less extensively ensheathed in horny beaks,
remind us of birds. Moreover, their bones con-
tained air cavities, rendering them specifically
Hehter, as is the case in most birds, The breast-
bone was laree and keeled, as in most birds and in
bats, and the shoulder girdle is strikingly similar
to that of ordinary birds. But, It seems to me,
that the special resemblance of pterodactyles to
birds ends here, unless I may add the entire absence
of teeth which characterizes the great pterodactyles
{Ptei^anodon), discovered by Professor Marsh. All
other known pterodactyles have teeth lodged In
sockets. In the vertebral column and the hind
limbs there are no special resemblances to birds,
and when we turn to the wings they are found
to be constructed on a totally different principle
from those of birds.
There are four fingers. These four fingers are
large, and three of them, those which answer to
the thumb and two following fingers in my hand —
are terminated by claws, while the fourth is
70 LECTURES ON EVOLUTION. [lect ir.
enormously prolonged and converted into a great
jointed style. You see at once, from what I have
stated about a bird's wing, that there could be
nothing less like a bird's wing than this is. It
was concluded by general reasoning that this finger
had the office of supporting a web which extended
between it and the body. An existing specimen
proves that such was really the case, and that
the pterodactyles were devoid of feathers, but that
the fingers supported a vast web like that of a
bat's wing , in fact, there can be no doubt that this
ancient reptile flew after the fashion of a bat.
Thus though the pterodactyle is a reptile which
has become modified in such a manner as to enable
it to fly, and therefore, as might be expected, pre-
sents some points of resemblance to other animals
which fly; it has, so to speak, gone off the line
which leads directly from reptiles to birds, and has
become disqualified for the changes which lead to
the characteristic organization of the latter class.
Therefore, viewed in relation to the classes of
reptiles and birds, the pterodactyles appear to me
to be, in a limited sense, intercalary forms ; but they
are not even approximately linear, in the sense of
exemplifying those modifications of structure through
which the passage from the reptile to the bird took
place.
LECTURE III.
THE DEMONSTRA'TIVE EVIDENCE OF EVOLUTION.
The occurrence of historical facts is said to be
demonstrated, when the evidence that they hap-
pened is of such a character as to render the
assumption that they did not happen in the highest
degree improbable ; and the question I now have
to deal wj.th is, whether evidence in favour of the
evolution of animals of this degree of cogency is,
or is no'., obtainable from the record of the suc-
cession of living forms which is presented to us
by fossil remains.
Those who have attended to the progress of
palaeoi itology are aware that evidence of the cha-
racter which I have defined has been produced in
considi -rable and continually - increasing quantity
during the last few years. Indeed, the amount and
the satisfactory nature of that evidence are some-
what surprising, when we consider the conditions
under w hich alone we can hope to obtain it.
72 LECTURES ON EVOLUTION. [lect. hi.
It is obviously useless to seek for such evidence,
except in localities in which the physical conditions
have been such as to permit of the deposit of an
unbroken, or but rarely interrupted, series of strata
through a long period cf time ; in which the group
of animals to be investigated has existed in such
abundance as to furnish the requisite supply of
remains ; and in which, finally, the materials com-
posing the strata are such aj to ensure the pre-
servation of these remains in a tolerably perfect
and undisturbed state.
It so happens that the case which, at present,
most nearly fulfils all these conditions is that of
the series of extinct animals which culminates in
the Horses ; by which term I mean to denote not
merely the domestic animals with which we are all
so well acquainted, but their allies, the r.ss, zebra,
quagga, and the like. In short, I use 'horses"
as the equivalent of the technical name .Eqiiidce,
which is applied to the whole group of existing
equine animals.
The horse is in many ways a remai'kable
animal ; not least so in the fact that it pn^sents
us with an example of one of the most f)erfect
pieces of machinery in the living world. In truth,
among the works of human ingenuity It cannot be
said that there is any locomotive so pe'.rfectly
adapted to its purposes, doing so much wo.'.'k with
LECT. III.] THE LIMBS OF THE HORSE. 73
so small a quantity of fuel, as this machine of
nature's manufacture — the horse. And, as a neces-
sary consequence of any sort of perfection, of
mechanical perfection as of others, you find that
the horse is a beautiful creature, one of the most
beautiful of all land-animals. Look at the perfect
balance of its form, and the rhythm and force of
its action. The locomotive machinery is, as you
are aware, resident in its slender fore and hind
limbs ; they are flexible and elastic levers, capable
of being moved by very powerful muscles ; and,
in order to supply the engines which work these
levers with the force which they expend, the horse
is provided with a very perfect apparatus for
o-rindine its food and extractino; therefrom the
requisite fuel.
Without attempting to take you very far into
the region of osteolog^ical detail, I must never-
theless trouble you with some statements respecting
the anatomical structure of the horse ; and, more
especially, will it be needful to obtain a general
conception of the structure of its fore and hind
limbs, and of its teeth. But I shall only touch
upon those points which are absolutely essential
to our inquiry.
Let us turn in the first place to the fore-limb.
In most quadrupeds, as in ourselves, the fore-arm
contains distinct bones called the radius and the
74 LECTURES ON EVOLUTION. [lect. )ii.
ulna. The corresponding region in the Horse
seem at first to possess but one bone. Careful
observation, however, enables us to distinguish in
this bone a part which clearly answers to the upper
end of the ulna. This is closely united with the
chief mass of the bone which represents the radius,
and runs out into a slender shaft which may be
traced for some distance downwards upon the back
of the radius, and then in most cases thins out and
vanishes. It takes still more trouble to make sure
of what is nevertheless the fact, that a small part
of the lower end of the bone of the horse's fore-
arm, which is only distinct in a very young foal,
is really the lower extremity of the ulna.
What is commonly called the knee of a horse
is its wrist. The " cannon bone " answers to the
middle bone of the five metacarpal bones, which
support the palm of the hand in ourselves. The
" pastern," " coronary," and " coffin " bones of ve-
terinarians answer to the joints of our middle
fingers, while the hoof is simply a greatly enlarged
and thickened nail. But if what lies below the
horse's " knee " thus corresponds to the middle
finger in ourselves, what has become of the four
other fingers or digits ? We find in the places of
the second and fourth digits only two slender
splint-like bones, about two-thirds as long as the
cannon bone, which gradually taper to their lower
LECT. III.] THE TEETH OF THE HORSE. 75
ends and bear no finger joints, or, as they are
termed, phalanges. Sometimes, small bony or gristly
nodules are to be found at the bases of these two
metacarpal splints, and it is probable that these
represent rudiments of the first and fifth toes.
Thus, the part of the horse's skeleton, which cor-
responds with that of the human hand, contains one
overgrown middle digit, and at least two imperfect
lateral digits ; and these answer, respectively, to the
third, the second, and the fourth fingers in man.
Corresponding modifications are found in the
hind limb. In ourselves, and in most quadrupeds,
the leg contains two distinct bones, a large bone, the
tibia, and a smaller and more slender bone, the fibula.
But, in the horse, the fibula seems, at first, to be
reduced to its upper end ; a short slender bone
united with the tibia, and ending in a point below,
occupying its place. Examination of the lower end
of a young foal's shin-bone, however, shows a dis-
tinct portion of osseous matter, which is the lower
end of the fibula ; so that the, apparently single,
lower end of the shin-bone is really made up of
the coalesced ends of the tibia and fibula, just as
the, apparently single, lower end of the fore-arm
bone is composed of the coalesced radius and
ulna.
The heel of the horse is the part commonly
known as the hock. The hinder cannon bone
76 LECTURES ON EVOLUTION. [lect. hi.
answers to the middle metatarsal bone of the
human foot, the pastern, coronary, and coffin bones,
to the middle toe bones ; the hind hoof to the nail ;
as in the fore-foot. And, as in the fore-foot,
there are merely two splints to represent the second
and the fourth toes. Sometimes a rudiment of a
fifth toe appears to be traceable.
The teeth of a horse are not less peculiar than
its limbs. The living engine, like all others, must
be well stoked if it is to do its work ; and the
horse, if it is to make good its wear and tear, and
to exert the enormous amount of force required for
its propulsion, must be well and rapidly fed. To
this end, good cutting instruments and powerful
and lasting crushers are needful. Accordingly, the
twelve cutting teeth of a horse are close-set and
concentrated in the fore part of its mouth, like so
many adzes or chisels. The grinders or molars are
large, and have an extremely complicated structure,
being composed of a number of different substances
of unequal hardness. The consequence of this is
that they wear away at different rates ; and, hence,
the surface of each grinder is always as uneven
as that of a grood millstone.
I have said that the structure of the grinding
teeth is very complicated, the harder and the
softer parts being, as it were, interlaced with one
another. The result of this is that, as the tooth
LECT. III.] THE TEETH OF THE HORSE. 77
wears, the crown presents a peculiar pattern, the
nature of which is not very easily deciphered at
first ; but which it is important we should under-
stand clearly. Each grinding tooth of the upper
jaw has an outer wall so shaped that, on the worn
crown, it exhibits the form of two crescents, one in
front and one behind, with their concave sides
turned outwards. From the inner side of the front
crescent, a crescentic front ridge passes inwards
and backwards, and its inner face enlarges into a
strone longitudinal fold or pillar. From the front
part of the hinder crescent, a back ridge takes a like
direction, and also has its pillar.
The deep interspaces or valleys between these
ridges and the outer wall are filled by bony sub-
stance, which is called ceme7tt, and coats the whole
tooth.
The pattern of the worn face of each grinding
tooth of the lower jaw is quite different. It appears
to be formed of two crescent-shaped ridges, the
convexities of which are turned outwards. The
free extremity of each crescent has a pillar, and
there is a large double pillar where the two
crescents meet. The whole structure is, as it were,
imbedded in cement, which fills up the valleys, as
in the upper grinders.
If the grinding faces of an upper and of a
lower molar of the same side are applied together,
78 LECTURES ON EVOLUTION. [lect. hi.
it will be seen that the apposed ridges are nowhere
parallel, but that they frequently cross ; and that
thus, in the act of mastication, a hard surface in
the one is constantly applied to a soft surface in
the other, and vice vei'sd. They thus constitute a
grinding apparatus of great efficiency, and one which
is repaired as fast as it wears, owing to the long-
continued growth of the teeth.
Some other peculiarities of the dentition of the
horse must be noticed, as they bear upon what
I shall have to say by and by. Thus the crowns
of the cutting teeth have a peculiar deep pit, which
gives rise to the well-known " mark " of the horse.
There is a large space between the outer incisors
and the front grinder. In this space the adult
male horse presents, near the incisors on each side,
above and below, a canine or " tush," which is
commonly absent in mares. In a young horse,
moreover, there is not unfrequently to be seen,
in front of the first grinder, a very small tooth,
which soon falls out. If this small tooth be
counted as one, it will be found that there are seven
teeth behind the canine on each side ; namely, the
small tooth in question, and the six great grinders,
among which, by an unusual peculiarity, the fore-
most tooth is rather larger than those which fol-
low it.
I have now enumerated those characteristic
LECT. III.] FOSSIL HORSES. 79
structures of the horse which are of most import-
ance for the purpose we have in view.
To any one who is acquainted with tiie morpho-
logy of vertebrated animals, they show that the
horse deviates widely from the general structure of
mammals; and that the horse type is, in many respects,
an extreme modification of the general mammalian
plan. The least modified mammals, in fact, have
the radius and ulna, the tibia and fibula, distinct
and separate. They have five distinct and com-
plete digits on each foot, and no one of these
digits is very much larger than the rest. More-
over, in the least modified mammals, the total
number of the teeth is very generally forty-four,
while in horses, the usual number is forty, and in
the absence of the canines, it may be reduced to
thirty-six ; the incisor teeth are devoid of the fold
seen in those of the horse : the grinders regularly
diminish in size from the middle of the series to
its front end ; while their crowns are short, early
attain their full length, and exhibit simple ridges or
tubercles, in place of the complex foldings of the
horse's grinders.
Hence the general principles of the hypothesis
of evolution lead to the conclusion that the horse
must have been derived from some quadruped which
possessed five complete digits on each foot ; which
had the bones of the fore-arm and of the leg complete
8o LECTURES ON EVOLUTION. [lect. iil
and separate ; and which possessed forty-four teeth,
among which the crowns of the incisors and grinders
had a simple structure; while the latter gradually
increased in size from before backwards, at any rate
in the anterior part of the series, and had short
crowns.
And if the horse has been thus evolved, and the
remains of the different stages of its evolution
have been preserved, they ought to present us
with a series of forms in which the number of
the diorits becomes reduced ; the bones of the fore-
arm and leg gradually take on the equine condition ;
and the form and arrangement of the teeth succes-
sively approximate to those which obtain in existing
horses.
Let us turn to the facts, and see how far they
fulfil these requirements of the doctrine of evolu-
tion.
In Europe abundant remains of horses are found
in the Quaternary and later Tertiary strata as far
as the Pliocene formation. But these horses, which
are so common in the cave-deposits and in the
gravels of Europe, are in all essential respects like
existinof horses. And that is true of all the horses
of the latter part of the Pliocene epoch. But, in
deposits which belong to the earlier Pliocene and
later Miocene epochs, and which occur in Britain,
in France, in Germany, in Greece, in India, we
LECT. III.] THE ANCHITHERIUM. 8r
find animals which are extremely like horses — •
which, in fact, are so similar to horses, that you
may follow descriptions given in works upon the
anatomy of the horse upon the skeletons of these
animals — but which differ in some important parti-
culars. For example, the structure of their fore and
hind limbs is somewhat different. The bones which,
in the horse, are represented by two splints, imper-
fect below, are as long as the middle metacarpal
and metatarsal bones ; and, attached to the extremity
of each, is a digit with three joints of the same
general character as those of the middle digit, only
very much smaller. These small digits are so dis-
posed that they could have had but very little
functional importance, and they must have been
rather of the nature of the dew-claws, such as are
to be found in many ruminant animals. The
Hipparion, as the extinct European three-toed
horse is called, in fact, presents a foot similar to
that of the American Protohippus (Fig. 9), except
that, in the Hipparion, the smaller digits are
situated farther back, and are of smaller propor-
tional size, than in the Protohippus.
The ulna is slightly more distinct than in the
horse ; and the whole length of it, as a very slender
shaft, intimately united with the radius, is completely
traceable. The fibula appears to be in the same
condition as in the horse. The teeth of the
82 LECTURES ON EVOLUTION. [lect. hi.
Hipparion are essentially similar to those of the
horse, but the pattern of the grinders is in some
respects a little more complex, and there is a
depression on the face of the skull in front of the
orbit, which is not seen in existing horses.
In the earlier Miocene, and perhaps the later
Eocene deposits of some parts of Europe, another
extinct animal has been discovered, which Cuvier,
who first described some fragments of it, considered
to be a PalcBotherium. But as further discoveries
threw new light upon its structure, it was recognised
as a distinct genus, under the name of AncJii-
therium.
In its general characters, the skeleton of Aiichi-
therium is very similar to that of the horse. In fact,
Lartet and De Blainville called it Palccotheriiwi
equmum or hippoides ; and De Christol, in 1847,
said that it differed from Hipparion in little more
than the characters of its teeth, and gave it the
nanie of Hipparitherium. Each foot possesses
three complete toes ; while the lateral toes are much
larger in proportion to the middle toe than in
Hipparion, and doubtless rested on the ground in
ordinary locomotion.
The ulna is complete and quite distinct from
the radius, though firmly united with the latter.
The fibula seems also to have been complete.
Its lower end, though intimately united with that
LECT. III.] THE ANCHITHERIUM. 83
of the tibia, is clearly marked off from the latter
bone.
There are forty-four teeth. The incisors have
no strong pit. The canines seem to have been
well developed in both sexes. The first of the
seven grinders, which, as I have said, is frequently
absent, and, when it does exist, is small in the
horse, is a good-sized and permanent tooth, while
the erinder which follows it is but little larger than
the hinder ones. The crowns of the grinders are
short, and though the fundamental pattern of the
horse-tooth is discernible, the front and back ridges
are less curved, the accessory pillars are wanting,
and the valleys, much shallower, are not filled up
with cement.
Seven years ago, when I happened to be looking
critically into the bearing of palaeontological facts
upon the doctrine of evolution, it appeared to me
that the Anchitheriurn, the Hipparion, and the
modern horses, constitute a series in which the
modifications of structure coincide with the order
of chronological occurrence, in the manner in
which they must coincide, if the modern horses
really are the result of the gradual metamor-
phosis, in the course of the Tertiary epoch, of
a less specialised ancestral form. And I found
by correspondence with the late eminent French
anatomist and palaeontologist, M. Lartet, that he
LECTURES ON EVOLUTION. [lect.
had arrived at the same conclusion from the
same data.
That the AncJiithe^'iiun type had become meta-
morphosed into the Hipparioii type, and the latter
into the Equine type, in the course of that period
of time which is represented by the latter half of
the Tertiary deposits, seemed to me to be the only
explanation of the facts for which there was even
a shadow of probability.'
And, hence, I have ever since held that these
facts afford evidence of the occurrence of evolution,
which, in the sense already defined, may be termed
demonstrative.
All who have occupied themselves with the
structure of AncJiitheriwn, from Cuvier onwards,
have acknowledged its many points of likeness to
a well-known genus of extinct Eocene mammals,
Palceotheriuin, Indeed, as we have seen, Cuvier
regarded his remains of AjicJiitherium as those
of a species of PalcEotherium. Hence, in attempt-
ing to trace the pedigree of the horse beyond
the Miocene epoch and the Anchitheroid form, I
' I use the word "type" because it is highly probable that many
forms of AncIitiheriu)ji-\ikQ and H ipparion-\\\i& animals existed in the
Miocene and Pliocene epochs, ju st as many species of the horse tribe
exist now ; and it is highly improbable that the particular species of
Anchitherium or Hipparion, which happen to have been discovered,
should be precisely those which have formed part of the direct line
of the horse's pedigree.
LECT. III.] AMERICAN HORSES. 85
naturally sought among the various species of
Paleeotheroid animals for its nearest ally, and I
was led to conclude that the Palaiotheidum minus
iPlagiolophus) represented the next step more nearly
than any form then known.
I think that this opinion was fully justifiable ;
but the progress of investigation has thrown an
unexpected light on the question, and has brought
us much nearer than could have been anticipated
to a knowledge of the true series of the progenitors
of the horse.
You are all aware that, when your country was
first discovered by Europeans, there were no traces
of the existence of the horse in any part of the
American Continent. The accounts of the conquest
of Mexico dwell upon the astonishment of the
natives of that country when they first became
acquainted with that astounding phenomenon — a
man seated upon a horse. Nevertheless, the in-
vestigations of American geologists have proved
that the remains of horses occur in the most
superficial deposits of both North and South
America, just as they do in Europe. Therefore,
for some reason or other — no feasible suggestion
on that subject, so far as I know, has been made
— the horse must have died out on this continent
at some period preceding the discovery of America.
Of late years there has been discovered In your
86 LECTURES ON EVOLUTION. [lect. hi.
Western Territories that marvellous accumulation
of deposits, admirably adapted for the preservation
of organic remains, to which I referred the other
evening, and which furnishes us with a consecutive
series of records of the fauna of the older half of
the Tertiary epoch, for which we have no parallel in
Europe. They have yielded fossils in an excellent
state of conservation and in unexampled number
and variety. The researches of Leidy and others
have shown that forms allied to the Hipparion
and the Anchitherium are to be found among
these remains. But it is only recently that the
admirably conceived and most thoroughly and
patiently worked-out investigations of Professor
Marsh have given us a just idea of the vast fossil
wealth, and of the scientific importance, of these
deposits. I have had the advantage of glancing
over the collections in Yale Museum ; and I can
truly say that, so far as my knowledge extends,
there is no collection from any one region and series
of strata comparable, for extent, or for the care with
which the remains have been got together, or for
their scientific importance, to the series of fossils
which he has deposited there. This vast collection
has yielded evidence bearing upon the question
of the pedigree of the horse of the most striking
character. It tends to show that we must look to
America, rather than to Europe, for the original seat
LECT. III.] AMERICAN HORSES. 87
of the equine series ; and that the archaic forms and
successive modifications of the horse's ancestry are
far better preserved here than in Europe.
Professor Marsh's kindness has enabled me to
put before you a diagram, every figure in which is
an actual representation of some specim.en which
is to be seen at Yale at this present time
(Fig- 9).
The succession of forms which he has brought
together carries us from the top to the bottom
of the Tertlaries. Firstly, there is the true horse.
Next we have the American Pliocene form of the
horse {P lioJiippus) ; in the conformation of its limbs
it presents some very slight deviations from the
ordinary horse, and the crowns of the grinding
teeth are shorter. Then comes the Protohippus,
which represents the European Hippario7i, having
one large digit and two small ones on each foot,
and the general characters of the fore-arm and leg
to which I have referred. But it is more valuable
than the European Hipparion for the reason that
it is devoid of some of the peculiarities of that
form — peculiarities which tend to show that the
European Plipparion is rather a member of a
collateral branch, than a form in the direct line of
succession. Next, in the backward order in time,
is the MioJiipptis, which corresponds pretty nearly
with the Anchitheriiun of Europe. It presents three
88
LECTURES ON EVOLUTION. [lect. hi:
ForePoot Hind Foot Fore-arm. Leg-. Upper Molar. Lowpv Mnlsr
RECENT.
PLIOCENE.
PLIOHIPPUS.
PROTOHIPPUS
(Hippat ion).
MIOHIPPUS
(A nchitlieriii »i)
MESOHiprus.
EOCENE.
OROHIPPUS
Fig. 9.
LECT. III.] DEMONSTRATIVE EVIDENCE. 89
complete toes — one large median and two smaller
lateral ones ; and there is a rudiment of that digit,
which answers to the little finger of the human
hand.
The European record of the pedigree of the horse
stops here ; in the American Tertiaries, on the
contrary, the series of ancestral equine forms is
continued into the Eocene formations. An older
Miocene form, termed Mesohipptis, has three toes
in front, with a large splint-like rudiment repre-
senting the little finger ; and three toes behind.
The radius and ulna, the tibia and the fibula, are
distinct, and the short crowned molar teeth are
anchitherioid in pattern.
But the most important discovery of all is the
Orohipptis, which comes from the Eocene formation,
and is the oldest member of the equine series, as
yet known. Here we find four complete toes on
the front-limb, three toes on the hind-limb, a well-
developed ulna, a well-developed fibula, and short-
crowned grinders of simple pattern.
Thus, thanks to these important researches, it
has become evident that, so far as our present
knowledge extends, the history of the horse-type
is exactly and precisely that which could have been
predicted from a knowledge of the principles of
evolution. And the knowledge we now possess
justifies us completely in the anticipation, that when
5
90 LECTURES ON EVOLUTION. [lect. iii.
the still lower Eocene deposits, and those which
belong to the Cretaceous epoch, have yielded up
their remains of ancestral equine animals, we shall
find, first, a form with four complete toes and a
rudiment of the innermost or first digit in front,
with, probably, a rudiment of the fifth digit in the
hind foot-; ^ while, in still older forms, the series of
the digits will be more and more complete, until
we come to the five-toed animals, in which, if the
doctrine of evolution is well founded, the whole
series must have taken its origin.
That is what I mean by demonstrative evi-
dence of evolution. An inductive hypothesis is
said to be demonstrated when the facts are
shown to be in entire accordance with it. If
that is not scientific proof, there are no merely
inductive conclusions which can be said to be
proved. And the doctrine of evolution, at the
present time, rests upon exactly as secure a foun-
dation as the Copernican theory of the motions
of the heavenly bodies did at the time of its pro-
mulgation. Its logical basis is precisely of the
same character — the coincidence of the observed
facts with theoretical requirements.
' Since this lecture was delivered, Professor Marsh has discovered
a new genus of equine mammals {Eohippiis) from the lowest Eocene
deposits of the West, which corresponds very nearly to this description.
— American Journal of Science, November, 1876.
LECT. iii.J EVOLUTION AND TIME. 91
The only way of escape, if it be a way of escape,
from the conclusions which I have just indicated, is
the supposition that all these different equine forms
have been created separately at separate epochs of
time ; and, I repeat, that of such an hypothesis as
this there neither is, nor can be, any scientific evi-
dence ; and, assuredly, so far as I know, there is none
which is supported, or pretends to be supported, by
evidence or authority of any other kind, I can but
think that the time will come when such suggestions
as these, such obvious attempts to escape the
force of demonstration, will be put upon the same
footing as the supposition made by some writers,
who are, I believe, not completely extinct at
present, that fossils are mere simulacra, are no
indications of the former existence of the animals
to which they seem to belong ; but that they are
either sports of Nature, or special creations, in-
tended— as I heard suggested the other day — to
test our faith.
In fact, the whole evidence is in favour of evo-
lution, and there is none against it. And I say
this, although perfectly well aware of tlie seeming
difficulties which have been built up upon what
appears to the uninformed to be a solid foundation.
I meet constantly with the argument that the doc-
trine of evolution cannot be well founded, because
it requires the lapse of a very vast period of time ;
92 LECTURES ON EVOLUTION. [[.ect. in,
while the duration of life upon the earth, thus
implied, is inconsistent with the conclusions arrived,
at by the astronomer and the physicist. I may
venture to say that I am familiar with those
conclusions, inasmuch as some years ago, when
President of the Geological Society of London,
I took the liberty of criticising them, and of
showing in what respects, as it appeared to me,
they lacked complete and thorough demonstration.
But, putting that point aside, suppose that, as the
astronomers, or some of them, and some physical
philosophers, tell us, it is impossible that life could
have endured upon the earth for as long a period
as is required by the doctrine of evolution — suppos-
ing that to be proved — I desire to be informed,
what is the foundation for the statement that
evolution does require so great a time ? The
bioloefist knows noth ine whatever of the amount
of time which may be required for the process of
evolution. It is a matter of fact that the equine forms,
which I have described to you occur, in the order
stated, in the Tertiary formations. But I have not
the slightest means of guessing whether it took
a million of years, or ten millions, or a hundred
millions, or a thousand millions of years, to give
rise to that series of chanofes. A bioloofist has
no means of arriving at any conclusion as to the
amount of time which may be needed for a certain
LECT. III.] EVOLUTION AND TIME. 93
quantity of organic change. He takes his time
from the geologist. The geologist, considering
the rate at which deposits are formed and the
rate at which denudation goes on upon the surface
of the earth, arrives at more or less justifiable
conclusions as to the time which is required for
the deposit of a certain thickness of rocks ; and if
he tells me that the Tertiary formations required
500,000,000 years for their deposit, I suppose he
has good ground for what he says, and I take tKat
as a measure of the duration of the evolution of
the horse from the Orohippus up to its present
condition. And, if he is right, undoubtedly evolu-
tion is a very slow process, and requires a great
deal of time. But suppose, now, that an astro-
nomer or a physicist — for instance, my friend Sir
William Thomson — tells me that my geological
authority is quite wrong; and that he has weighty
evidence to show that life could not possibly have
existed upon the surface of the earth 500,000,00c
years ago, because the earth would have then beer:
too hot to allow of life, my reply is : " That
is not my affair ; setde that with the geologist,
and when you have come to an agreement among
yourselves I will adopt your conclusion." We
take our time from the geologists and physicists ;
and it is monstrous that, having taken our time
from the physical philosopher's clock, the physical
94 LECTURES ON EVOLUTION. [lect. hi.
philosopher should turn round upon us, and say
we are too fast or too slow. What we desire
to know is, is it a fact that evolution took place ?
As to the amount of time which evolution may
have, occupied, we are in the hands of the phy-
sicist and the astronomer, whose business it is to
deal with those questions.
I have now, ladies and gentlemen, arrived at
the conclusion of the task which I set before
myself when I undertook to deliver these lectures.
My purpose has been, not to enable those among
you who have paid no attention to these subjects
before, to leave this room in a condition to decide
upon the validity or the invalidity of the hypothesis
of evolution ; but I have desired to put before you
the principles upon which all hypotheses respecting
the history of Nature must be judged ; and further-
more, to make apparent the nature of the evidence
and the amount of cogency which is to be ex-
pected and may be obtained from it. To this end,
I have not hesitated to regard you as genuine
students and persons desirous of knowing the
truth. I have not shrunk from taking you through
long discussions, that I fear may have sometimes
tried your patience ; and I have inflicted upon you
details which were indispensable, but which may
well have been wearisome. But I shall rejoice — ■
LECT. III.] EPILOGUE. 95
I shall consider that I have done you the greatest
service which it was In my power to do — if I have
thus convinced you that the great question which
we have been discussing is not one to be dealt
with by rhetorical flourishes, or by loose and
superficial talk ; but that it requires the keen
attention of the trained intellect and the patience
of the accurate observer.
When I commenced this series of lectures, I did
not think it necessary to preface them with a pro-
logue, such as might be expected from a stranger
and a foreigner ; for during my brief stay in your
country, I have found it very hard to believe that
a stranger could be possessed of so many friends,
and almost harder that a foreigner could express
himself in your language in such a way as to be,
to all appearance, so readily intelligible. So
far as I can judge, that most intelligent, and,
perhaps, I may add, most singularly active and
enterprising body, your press reporters, do not seem
to have been deterred by my accent from giving
the fullest account of everything that I happen
to have said.
But the vessel in which I take my departure
to-morrow morning is even now ready to slip
her moorings ; I awake from my delusion that
I am other than a stranger and a foreigner. I
am ready to go back to my place and country ;
96 LECTURES ON EVOLUTION. [lect. hi.
but, before doing so, let me, by way of epilogue,
tender to you my most hearty thanks for the kind
and cordial reception which you have accorded
to me ; and let me thank you still more for that
which is the greatest compliment which can be
afforded to any person in my position — the con-
tinuous and undisturbed attention which you have
bestowed upon the long argument which I have
had the honour to lay before you.
BALTIMORE.
ADDRESS
UNIVERSITY EDUCATION.
ADDRESS
UNIVERSITY EDUCATION.^
The actual work of the University founded in this
city by the well-considered munificence of Johns
Hopkins commences to-morrow, and among the
many marks of confidence and good-will which
have been bestowed upon me in the United
States, there is none which I value more highly
than that conferred by the authorities of the
University when they invited me to deliver an
address on such an occasion.
For the event which has brought us together
is, in many respects, unique. A vast property
is handed over to an administrative body, ham-
' Delivered at the formal opening of the Johns Hopkins University
at Baltimore, U.S., September 12. The total amount bequeathed by
Johns Hopkins is more than 7,000,000 dollars. The sum of 3,500,000
dollars is appropriated to a university, a like sum to a hospital, and
the rest to local institutions of education and charity.
ON UNIVERSITY EDUCATION.
pered by no conditions save these ; — That the
principal shall not be employed in building : that
the funds shall be appropriated, in equal propor-
tions, to the promotion of natural knowledge and
to the alleviation of the bodily sufferings of man-
kind ; and, finally, that neither political nor
ecclesiastical sectarianism shall be permitted to
disturb the impartial distribution of the testator's
benefactions.
In my experience of life a truth which sounds
very much like a paradox has often asserted itself;
namely, that a man's worst difficulties begin when
he is able to do as he likes. So long as a man
is strucfSflinof with obstacles he has an excuse for
failure or shortcoming ; but when fortune removes
them all and gives him the power of doing as
he thinks best, then comes the time of trial.
There is but one right, and the possibilities of
wrong are infinite. I doubt not that the trustees
of the Johns Hopkins University felt the full
force of this truth when they entered on the
administration of their trust a year and a half
ago ; and I can but admire the activity and
resolution which have enabled them, aided by the
able president whom they have selected, to lay
down the great outlines of their plan, and carry
it thus far into execution. It is impossible to
study that plan without perceiving that great care,
ELEMENTARY EDUCATION. loi
forethought, and sagacity, have been bestowed
upon it, and that it demands the most respectful
consideration, I have been endeavouring to as-
certain how far the principles which underHe it
are in accordance with those which have been
estabhshed in my own mind by much and long-
continued thought upon educational questions.
Permit me to place before you the result of my
reflections.
Under one aspect a university is a particular
kind of educational institution, and the views
which we may take of the proper nature of a
university are corollaries from those which we
hold respecting education in general. I think it
must be admitted that the school should prepare
for the university, and that the university should
crown the edifice, the foundations of which are
laid in the school. University education should
not be something distinct from elementary edu-
cation, but should be the natural outgrowth and
development of the latter. Now I have a very
clear conviction as to what elementary education
ought to be ; what it really may be, when properly
organised ; and what I think it will be, before
many years have passed over our heads, in England
and in America. Such education should enable
an average boy of fifteen or sixteen to read
and write his own lanq-uagre with ease and
ON UNIVERSITY EDUCATION.
accuracy, and with a sense of literary excellence
derived from the study of our classic writers :
to have a general acquaintance with the history
of his own country and with the great laws of
social existence ; to have acquired the rudiments
of the physical and psychological sciences, and
a fair knowledge of elementary arithmetic and
geometry. He should have obtained an acquaint-
ance with logic rather by example than by precept ;
while the acquirement of the elements of music
and drawing should have been pleasure rather
than work.
It may sound strange to many ears if I venture
to maintain the proposition that a young person,
educated thus far, has had a liberal, though per-
haps not a full, education. But it seems to me
that such training as that to which I have re-
ferred may be termed liberal, in both the senses in
which that word is employed, with perfect accuracy.
In the first place, it is liberal in breadth. It
extends over the whole ground of things to be
known and of faculties to be trained, and it gives
equal importance to the two great sides of human
activity — art and science. In the second place,
it is liberal in the sense of being an education
fitted for free men ; for men to whom every career
is open, and from whom their country may demand
that they should be fitted to perform the duties
EDUCATIONAL SELECTION. 103
of any career. I cannot too strongly impress
upon you the fact that, with such a primary edu-
cation as this, and with no more than is to be
obtained by building strictly upon its lines, a man
of ability may become a great writer or speaker,
a statesman, a lawyer, a man of science, painter,
sculptor, architect, or musician. That even develop-
ment of all a man's faculties, which is what properly
constitutes culture, may be effected by such an edu-
cation, while it opens the way for the indefinite
strengthening of any special capabilities with
which he may be gifted.
In a country like this, where most men have
to carve out their own fortunes and devote them-
selves early to the practical affairs of life, com-
paratively few can hope to pursue their studies
up to, still less beyond, the age of manhood. But
it is of vital importance to the welfare of the
community that those who are relieved from the
need of making a livelihood, and still more, those
who are stirred by the divine impulses of intellectual
thirst or artistic genius, should be enabled to
devote themselves to the higher service of their
kind, as centres of intelligence, interpreters of
nature, or creators of new forms of beauty. And
it is the function of a university to furnish such
men with the means of becoming that which it is
their privilege and duty to be. To this end
I04 ON UNIVERSITY EDUCATION.
the university need cover no ground foreic^n to
that occupied by the elementary school. Indeed
it cannot ; for the elementary instruction which
I have referred to embraces all the kinds of real
knowledge and mental activity possible to man.
The university can add no new departments of
knowledge, can offer no new fields of mental
activity ; but what it can do is to intensify and
specialise the instruction in each department.
Thus literature and philology, represented in the
elementary school by English alone, in the uni-
versity will extend over the ancient and modern
languages. History, which, like charity, best
begins at home, but, like charity, should not end
there, will ramify into anthropology, archseology,
political history, and geography, with the history
of the growth of the human mind and of its pro-
ducts in the shape of philosophy, science, and art.
And the university will present to the student
libraries, museums of antiquities, collections of
coins, and the like, which will efficiently subserve
these studies. Instruction in the elements of
social economy, a most essential, but hitherto
sadly-neglected part of elementary education, will
develop in the university into political economy,
sociology, and law. Physical science will have
its great divisions of physical geography, with
geology and astronomy ; physics ; chemistry and
PRIMARY AND SECONDARY SCHOOLS. 105
biology ; represented not merely by professors and
their lectures, but by laboratories, in which the
students, under guidance of demonstrators, will
work out facts for themselves and come into that
direct contact with reality which constitutes the
fundamental distinction of scientific education.
Mathematics will soar into its highest regions ;
while the high peaks of philosophy may be scaled
by those whose aptitude for abstract thought has
been awakened by elementary logic. Finally,
schools of pictorial and plastic art, of architecture,
and of music, will offer a thorough discipline
in the principles and practice of art to those in
whom lies nascent the rare faculty of aesthetic
representation, or the still rarer powers of creative
genius.
The primary school and the university are the
alpha and omega of education. Whether institutions
intermediate between these (so-called secondary
schools) should exist, appears to me to be a
question of practical convenience. If such schools
are established, the important thing is that they
should be true intermediaries between the primary
school and the university, keeping on the wide
track of general culture, and not sacrificing one
branch of knowledge for another.
Such appear to me to be the broad outlines of the
relations which the university, regarded as a place
io6 ON UNIVERSITY EDUCATION.
of education, ought to bear to the school, but a
number of points of detail require some considera-
tion, however briefly and imperfectly I can deal
with them. In the first place, there is the import-
ant question of the limitations whirch should be
fixed to the entrance into the university ; or, what
qualifications should be required of those who
propose to take advantage of the higher training
offered by the university. On the one hand, it
is obviously desirable that the time and oppor-
tunities of the university should not be wasted
in conferring such elementary instruction as can
be obtained elsewhere ; while, on the other hand,
it is no less desirable that the higher instruction
of the university should be made accessible to
every one who can take advantage of it, although
he may not have been able to go through any
very extended course of education. My own
feeling is distinctly against any absolute and defined
preliminary examination, the passing of which shall
be an essential condition of admission to the
university. I would admit to the university any one
who could be reasonably expected to profit by the
instruction offered to him ; and I should be inclined,
on the whole, to test the fitness of the student,
not by examination before he enters the university,
but at the end of his first term of study. If, on
examination in the branches of knowledge to which
FREE STUDY, OR A CURRICULUM. 107
he has devoted himself, he show himself deficient
in industry or in capacity, it will be best for the
university and best for himself, to prevent him
from pursuing a vocation for which he is obviously
unfit. And I hardly know of any other method
than this by which his fitness or unfitness can be
safely ascertained, though no doubt a good deal may
be done, not by formal cut and dried examination,
but by judicious questioning, at the outset of his
career.
Another very important and difficult practical
question is, whether a definite course of study shall
be laid down for those who enter the university ;
whether a curriculum shall be prescribed ; or
whether the student shall be allowed to rancre at
will among the subjects which are open to him.
And this question is inseparably connected with
another, namely, the conferring of degrees. It is
obviously impossible that any student should pass
throueh the whole of the series of courses of
instruction offered by a university. If a degree
is to be conferred as a mark of proficiency in
knowledge, it must be given on the ground that
the candidate is proficient in a certain fraction of
those studies ; and then will arise the necessity
of insuring an equivalency of degrees, so that the
course by which a degree is obtained shall mark
approximately an equal amount of labour and of
ON UNIVERSITY EDUCATION.
acquirements, in all cases. But this equivalency
can hardly be secured in any other way than by
prescribing a series of definite lines of study.
This is a matter which will require grave con-
sideration. The important points to bear in mind,
I think, are that there should not be too many
subjects in the curriculum, and that the aim should
be the attainment of thorouofh and sound knowledge
of each.
One half of the Johns Hopkins bequest is
devoted to the establishment of a hospital, and
it was the desire of the testator that the university
and the hospital should co-operate in the promotion
of medical education. The trustees will un-
questionably take the best advice that is to be
had as to the construction and administration of
the hospital. In respect to the former point,
they will doubtless remember that a hospital
may be so arranged as to kill more than it cures ;
and, in regard to the latter, that a hospital may
spread the spirit of pauperism among the well-
to-do, as well as relieve the sufferings of the
destitute. It is not for me to speak on these
topics — rather let me confine myself to the one
matter on which my experience as a student of
medicine, and an examiner of long standing, who
has taken a great interest in the subject of medical
education, may entitle me to a hearing. I mean
MEDICAL EDUCATION. 109
the nature of medical education itself, and the
co-operation of the university in its promotion.
What is the .object of medical education ? It
is to enable the practitioner, on the one hand, to
prevent disease by his knowledge of hygiene ;
on the other hand, to divine its nature, and to
alleviate or cure it, by his knowledge of pathology,
therapeutics, and practical medicine. That is his
business in life, and if he has not a thorough
and practical knowledge of the conditions of health,
of the causes which tend to the establishment
of disease, of the meaning of symptoms, and of
the uses of medicines and operative appliances,
he is incompetent, even if he were the best
anatomist, or physiologist, or chemist, that ever
took a gold medal or won a prize certificate.
This is one great truth respecting medical education.
Another is, that all practice in medicine is based
upon theory of some sort or other ; and therefore,
that it is desirable to have such theory in the
closest possible accordance with fact. The veriest
empiric who gives a drug in one case because he
has seen it do good in another of apparently the
same sort, acts upon the theory that similarity
of superficial symptoms means similarity of lesions ;
which, by the way, is perhaps as wikl an hypothesis
as could be invented. To understand the nature
of disease we must understand health, and the
ON UNIVERSITY EDUCATION.
understanding of the healthy body means the
having a knowledge of its structure and of the
way in which its manifold actions are performed,
which is what is technically termed human anatomy
and human physiology. The physiologist again
must needs possess an acquaintance with physics
and chemistry, inasmuch as physiology is, to a great
extent, applied physics and chemistry. For ordinary
purposes a limited amount of such knowledge is all
that is needful ; but for the pursuit of the higher
branches of physiology no knowledge of these
branches of science can be too extensive, or too
profound. Again, what we call therapeutics, which
has to do with the action of drugs and medicines
on the living organism, is, strictly speaking, a
branch of experimental physiology, and is daily
receiving a greater and greater experimental de-
velopment.
The third great fact which is to be taken into
consideration in dealing with medical education,
is that the practical necessities of l^fe do not, as
a rule, allow asptrants to medical practice to crive
more than three, or it may be four years to their
studies. Let us put it at four years, and then
reflect that, in the course of this time, a youna
man fresh from school has to acquaint himself with
medicine, surgery, obstetrics, therapeutics, pathology,
hygiene, as well as with the anatomy and the
ESSENTIALS AND NON-ESSENTIALS. m
physiology of the human body ; and that his
knowledge should be of such a character that it
can be relied upon in any emergency, and always
ready for practical application. Consider, in ad-
dition, that the medical practitioner may be called
upon, at any moment, to give evidence in a court
of justice in a criminal case ; and that it is therefore
well that he should know something of the laws
of evidence, and of what we call medical juris-
prudence. On a medical certificate, a man may
be taken from his home and from his business
and confined in a lunatic asylum ; surely, therefore,
it is desirable that the medical practitioner should
have some rational and clear conceptions as to
the nature and symptoms of mental disease. Bearing
in mind all these requirements of medical education,
you will admit that the burden on the young
aspirant for the medical profession is somewhat
of the heaviest, and that it needs some care to
prevent his intellectual back from being broken.
Those who are acquainted with the existing
systems of medical education will observe that,
lono- as is the catalocjue of studies which I have
enumerated, I have omitted to mention several (
that enter into the usual medical curriculum of the \
present day. I have said not a word about zoology, /
comparative anatomy, botany, or materia medica. • '
Assuredly this is from no light estimate of the '
ON UNIVERSITY EDUCATION.
value or importance of such studies in themselves.
It may be taken for granted that I should be the
last person in the world to object to the teaching
of zoology, or comparative anatomy, in themselves ;
but I have the strongest feeling that, considering
the number and the gravity of those studies through
which a medical man must pass, if he is to be
competent to discharge the serious duties which
devolve upon him, subjects which lie so remote as
these do from his practical pursuits should be
rigorously excluded. The young man, who has
enough to do in order to acquire such familiarity
with the structure of the human body as will enable
him to perform the operations of surgery, ought
not, in my judgment, to be occupied with investi-
gations into the anatomy of crabs and starfishes.
Undoubtedly the doctor should know the common
poisonous plants of his own country when he sees
them ; but that knowledge may be obtained by a
few hours devoted to the examination of specimens
of such plants, and the desirableness of such
knowledge is no justification, to my mind, for
spending three months over the study of systematic
botany. Again, materia medica, so far as it is a
knowledge of drugs, is the business of the druggist.
In all other callings the necessity of the division of
labour is fully recognised, and it is absurd to require
of the medical man that he should not avail himself
DEPTH BETTER THAN BREADTH. 113
of the special knowledge of those whose business
it is to deal in the drugs which he uses. It is all
very well that the physician should know that
castor oil comes from a plant, and castoreum from
an animal, and how they are to be prepared ; but
for all the practical purposes of his profession that
knowledge is not of one whit more value, has no
more relevancy, than the knowledge of how the
steel of his scalpel is made.
All knowledge is good. It is impossible to say
that any fragment of knowledge, however insigni-
ficant or remote from one's ordinary pursuits, may
not some day be turned to account. But in medical
education, above all things, it is to be recollected
that, in order to know a little well, one must be
content to be ignorant of a great deal.
Let it not be supposed that I am proposing to
narrow medical education, or, as the cry is, to lower
the standard of the profession. Depend upon it
there is only one way of really ennobling any call-
ing, and that is to make those who pursue it real
masters of their craft, men who can truly do that
which they profess to be able to do, and which they
are credited with being able to do by the public.
And there is no position so ignoble as that of the
so-called "liberally-educated practitioner," who, as
Talleyrand said of his physician, " Knows every-
thing, even a little physic ; " who may be able to
6
114 ON UNIVERSITY EDUCATION.
read Galen in the original ; who knows all the plants,
from the cedar of Lebanon to the hyssop upon the
wall ; but who finds himself, with the Issues of life
and death in his hands, ignorant, blundering, and
bewildered, because of his ignorance of the essential
and fundamental truths upon which practice must
be based. Moreover, I venture to say, that any
man who has seriously studied all the essential
branches of medical knowledge ; who has the
needful acquaintance with the elements of physical
science ; who has been brought by medical juris-
prudence into contact with law ; whose study of in-
sanity has taken him Into the fields of psychology ;
has ipso facto received a liberal education.
Having lightened the medical curriculum by
culling out of it everything which is unessential,
we may next consider whether something may not
be done to aid the medical student toward the
acquirement of real knowledge by modifying the
system of examination. In England, within my
recollection, it was the practice to require of the
medical student attendance on lectures upon the most
diverse topics during three years; so that it often
happened that he would have to listen, in the course
of a day, to four or five lectures upon totally different
subjects, in addition to the hours given to dissection
and to hospital practice : and he was required to
keep all the knowledge he could pick up, in this
EXAMINATIONS. 115
distracting fashion, at examination point, until, at the
end of three years, he was set down to a table and
questioned pell-mell upon all the different matters
with which he had been striving to make acquaint-
ance. A worse system and one more calculated to
obstruct the acquisition of sound knowledge and to
give full play to the "crammer" and the "grinder"
could hardly have been devised by human ingenuity.
Of late years great reforms have taken place.
Examinations have been divided so as to diminish
the number of subjects among which the attention
has to be distributed. Practical examination has
been largely introduced ; but there still remains,
even under the present system, too much of the old
evil inseparable from the contemporaneous pursuit
of a multiplicity of diverse studies.
Proposals have recently been made to get rid
of general examinations altogether, to permit the
student to be examined in each subject at the end
of his attendance on the class ; and then, in case of
the result being satisfactory, to allow him to have
done with it ; and I may say that this method has
been pursued for m.any years in the Royal School of
Mines in London, and has been found to work very
w^ell. It all''vs the student to concentrate his mind
upon what he is about for the time being, and then
to dismiss it. Those who are occupied in intel-
lectual work, will, I think, agree with me that it is
ii6 ON UNIVERSITY EDUCATION.
important, not so much to know a thino-, as to have
known it, and known it thoroughly. If you have
once known a thing in this way it is easy to renew
your knowledge when you have forgotten it ; and
when you begin to take the subject up again, it
slides back upon the familiar grooves with great
facility.
Lastly comes the question as to how the uni-
y versity may co-operate in advancing medical edu-
f cation. A medical school is strictly a technical
\^ school — a school in which a practical profession is
taught — while a university ought to be a place in
which knowledge is obtained without direct reference
• to professional purposes. It is clear, therefore, that
a university and its antecedent, the school, may best
co-operate with the medical school by making due
^ provision for the study of those branches of know-
^-' ledge which lie at the foundation of medicine.
At present, young men come to the medical
schools without a conception of even the elements
of physical science ; they learn, for the first time,
that there are such sciences as physics, chemistry,
and physiology, and are introduced to anatomy
as a new thing. It may be safely said that, with
a large proportion of medical stude<-its, much of
the first session is wasted in learninof how to learn
■ — in familiarising themselves with utterly strange
conceptions, and in awakening their dormant and
PREPARATORY MEDICAL EDUCATION. 117
wholly untrained powers of observation and of
manipulation. It is difficult to over estimate the
magnitude of the obstacles which are thrown in
the way of scientific training by the existing system
of school education. Not only are men trained
in mere book-work, ignorant of what observation
means, but the habit of learning from books alone
begets a disgust of observation. The book-learned
student will rather trust to what he sees in a book
than to the witness of his own eyes.
There is not the least reason why this
should be so, and, in fact, when elementary
education becomes that which I have assumed it 1
oucjht to be, this state of thlnors will no lonoer
exist. There is not the slightest difficulty in 1
giving sound elementary instruction in physics, \
in chemistry, and in the elements of human /
physiology, in ordinary schools. In other words, "^
there is no reason why the student should not /
come to the medical school, provided with as i
much knowledge of these several sciences as he /
ordinarily picks up, in the course of his first year |
of attendance, at the medical school. ^
I am not saying this without full practical
justification for the statement. For the last
eighteen years we have had in England a system
of elementary science teaching carried out undt-r
the auspices of the Science and Art Department,
ii8 ON UNIVERSITY EDUCATION.
by which elementary scientific instruction is made
readily accessible to the scholars of all the ele-
mentary schools in the country. Commencing
with small beginnings, carefully developed and
improved, that system now brings up for exami-
nation as many as seven thousand scholars in
the subject of human physiology alone. I can
say that, out of that number, a large proportion
have acquired a fair amount of substantial know-
ledge ; and that no inconsiderable percentage show
as good an acquaintance with human physiology
as used to be exhibited by the average candidates
for medical degrees in the University of London,
when I was first an examiner there twenty years
ago ; and quite as much knowledge as is possessed
by the ordinary student of medicine at the present
day. I am justified, therefore, in looking forward
to the time when the student who proposes to
devote himself to medicine will come, not abso-
lutely raw and inexperienced as he is at present,
but in a certain state of preparation for further
study ; and I look to the university to help him
still further forward in that stage of preparation,
through the organisation of its biological depart-
ment. Here the student will hnd means of
acquainting himself with the phenomena of life
jj, in their broadest acceptation. He will study not
• botany and zoology, which, as I have said, would
INTERPRETERS OF NATURE. 119
take him too far away from his ultimate goal ;
but, by duly arranged instruction, combined with
work in the laboratory upon the leading types of
animal and vegetable life, he will lay a broad, and
at the same time solid, foundation of biological
knowledge ; he will come to his medical studies
with a comprehension of the great truths of
morphology and of physiology, with his hands
trained to dissect and his eyes taught to see. I
have no hesitation in saying that such preparation
is worth a full year added on to the medical
curriculum. In other words, it will set free that
much time for attention to those studies which
bear directly upon the student's most grave and
serious duties as a medical practitioner.
Up to this point I have considered only the
teaching aspect of your great foundation, that
function of the university in virtue of which it
plays the part of a reservoir of ascertained truth,
so far as our symbols can ever interpret nature.
All can learn ; all can drink of this lake. It is
given to few to add to the store of knowledge,
to strike new springs of thought, or to shape
new forms of beauty. But so sure as it is that
men live not by bread, but by ideas, so sure is
it that the future of the world lies In the hands
of those who are able to carry the interpretation
of nature a step further than their predecessors ;
L
120 ON UNIVERSITY EDUCATION.
so certain is it that the highest function of a
university is .to seek out those men, cherish them,
and give their abihty to serve their kind full
play.
/ I rejoice to observe that the encouragement of
research occupies so prominent a place in your
official documents, and in the wise and liberal
inaugural address of your president. This subject
of the encouragement, or, as it is sometimes called,
the endowment of research, has of late years
greatly exercised the minds of men in England.
It was one of the main topics of discussion by
the members of the Royal Commission of whom
I was one, and who not long since issued their
report, after five years' labour. Many seem to
think that this question is mainly one of money ;
that you can go into the market and buy research,
and that supply will follow demand, as in the
ordinary course of commerce. This view does
not commend itself to my mind. I know of no
more difficult practical problem than the discovery
of a method of encouraging and supporting the
original investigator without opening the door to
nepotism and jobbery. My own conviction is
admirably summed up in the passage of your
president's address, " that the best investigators
are usually those who have also the responsibilities
of instruction, gaining thus the incitement of
ARCHITECTURE AND ACCOMMODATION. 121
colleagues, the encouragement of pupils, and the
observation of the public/'
At the commencement of this address I ventured
to assume that I might, if I thought fit, criticise
the arrangements which have been made by the
board of trustees, but I confess that I have little to
do but to applaud them. Most wise and sagacious
seems to me the determination not to build for
the present. It has been my fate to see great
educational funds fossilise into mere bricks and
mortar, in the petrifying springs of architecture,
with nothing left to work the institution they were
intended to support. A great warrior is said to
have made a desert and called it peace. Ad-
ministrators of educational funds have sometimes
made a palace and called It a university. If I
may venture to give advice In a matter which
lies out of my proper competency, I would say
that whenever you do build, get an honest brick-
layer, and make him build you just such rooms as
you really want, leaving ample space for expansion.
And a century hence, when the Baltimore and
Ohio shares are at one thousand premium, and
you have endowed all the professors you need,
and built all the laboratories that arc wanted, and
have the best museum and the finest library that
can be Imagined ; then, if you have a few hundred
thousand dollars you don't know what to do with.
122 ON UNIVERSITY EDUCATION.
send for an architect and tell him to put up a
facade. If American is similar to English ex-
perience, any other course will probably lead you
into having some stately structure, good for your
architect's fame, but not in the least what you
want.
It appears to me that what I have ventured to
lay down as the principles which should govern
the relations of a university to education in general,
are entirely in accordance with the measures you
have adopted. You have set no restrictions upon
access to the instruction you propose to give ;
you have provided that such instruction, either
as given by the university or by associated Institu-
tions, should cover the field of human intellectual
activity. You have recognised the importance of
encouraging research. You propose to provide
means by which young men, who may be full of
zeal for a literary or for a scientific career, but who
also may have mistaken aspiration for Inspiration,
may bring their capacities to a test, and give their
powers a fair trial. If such a one fail, his en-
dowment terminates, and there is no harm done.
If he succeed, you may give power of flight to the
genius of a Davy or a Faraday, a Carlyle or a
Locke, whose influence on the future of his fellow-
men shall be absolutely Incalculable.
You have enunciated the principle that " the
THE GOVERNING BODY. 123
glory of the university should rest upon the
character of the teachers and scholars, and not
upon their numbers or buildings constructed for
their use." And I look upon it as an essential
and most important feature of your plan that the
income ol the" professors and teachers shall be
independent of the number of students whom they
can'^ttract. In this way you provide against the
danger, patent elsewhere, of finding attempts at
improvement obstructed by vested interests ; and,
in the department of medical education especially,
you are free of the temptation to set loose upon
the world men utterly incompetent to perform the
serious and responsible duties of their profession.
It is a delicate matter for a stranger to the
practical working of your institutions, like myself,
to pretend to give an opinion as to the organisation
of your governing power. I can conceive nothing
better than that it should remain as it is, if you can
secure a succession of wise, liberal, honest, and con-
scientious men to fill the vacancies that occur among
you. I do not greatly believe in the efficacy of
any kind of machinery for securing such a result ;
but I would venture to suggest that the exclusive
adoption of the method of co-optation for filling the
vacancies which must occur in your body, appears
to me to be somewhat like a tempting of Providence.
Doubtless there are grave practical objections to
124 ON UNIVERSITY EDUCATION.
the appointment of persons outside of your body,
and not directly interested in the welfare of the
university ; but might it not be well if there were
an understanding that your academic staff should
be officially represented on the board, perhaps even
the heads of one or two independent learned bodies,
so that academic opinion and the views of the
outside world might have a certain influence in that
most important matter, the appointment of your
professors ? I throw out these suggestions, as I
have said, in ignorance of the practical difficulties
that may lie in the way of carrying them into effect,
on the general ground that personal and local in-
fluences are very subtle, and often unconscious,
while the future greatness and efficiency of the
noble institution which now commences its work
must largely depend upon its freedom from them.
I constantly hear Americans speak of the charm
which our old mother country has for them, of the
delio-ht with which they wander through the streets
of ancient towns, or climb the battlements of
mediaeval strongholds, the names of which are in-
dissolubly associated with the great epochs of that
noble literature which is our common inheritance;
or with the blood-stained steps of that secular
progress, by which the descendants of the savage
Britons and of the wild pirates of the North Sea
HOPES AND FEARS. 125
have become converted into warriors of order and
champions of peaceful freedom, exhausting what
still remains of the old Berserk spirit in subduing
nature, and turning the wilderness into a garden.
But anticipation has no less charm than retrospect,
and to an Englishman landing upon your shores for
the first time, travelling for hundreds of miles
through stringfs of grreat and well-ordered cities,
seeing your enormous actual, and almost infinite
potential, wealth in all commodities, and in the
energy and ability which turn wealth to account,
there is something sublime in the vista of the future.
Do not suppose that I am pandering to what is
commonly understood by national pride. I cannot
say that I am in the slightest degree impressed by
your bigness, or your material resources, as such.
Size is not grandeur, and territory does not make
a nation. The great issue, about which hangs a
true sublimity, and the terror of overhanging fate,
is what are you going to do with all these things ?
What is to be the end to which these are to be
the means ? You are making a novel experiment
in politics on the greatest scale which the world
has yet seen. Forty millions at your first centenary,
it is reasonably to be expected that, at the second,
these states will be occupied by two hundred
millions of English-speaking" people, spread over
an area as large as that of Europe, and with climates
126 ON UNIVERSITY EDUCATION.
and interests as diverse as those of Spain and
Scandinavia, England and Russia. You and your
descendants have to ascertain whether this crreat
mass will hold tosfether under the forms of a re-
public, and the despotic reality of universal suffrage;
whether state rights will hold out arainst centrali-
sation, without separation ; whether centralisation
will get the better, without actual or disguised
monarchy ; whether shifting corruption is better
than a permanent bureaucracy ; and as population
thickens in your great cities, and the pressure of
want is felt, the gaunt spectre of pauperism will
stalk among you, and communism and socialism will
claim to be heard. Truly America has a great
future before her ; great in toil, in care, and in re-
sponsibility ; great in true glory if she be guided in
wisdom and righteousness ; great in shame if she fail.
I cannot understand why other nations should envy
you, or be blind to the fact that it is for the highest
interest of mankind that you should succeed ; but
the one condition of success, your sole safeguard,
is the moral worth and intellectual clearness of the
individual citizen. Education cannot give these,
but it may cherish them and bring them to the front
in whatever station of society they are to be found ;
and the universities ought to be, and may be, the
fortresses of the hio^her life of the nation.
May the university which commences its practical
NON OMNIS MORIAR. 127
activity to-morrow abundantly fulfil its high purposes
may its renown as a seat of true learning, a centre
of free inquiry, a focus of intellectual light, increase
year by year, until men wander hither from all parts
of the earth, as of old they sought Bologna, or
Paris, or Oxford,
And it is pleasant to me to fancy that, among
the English students who are drawn to you at that
time, there may linger a dim tradition that a country-
man of theirs was permitted to address you as he
has done to-day, and to feel as if your hopes were
his hopes and your success his joy.
LONDON.
LECTURE
STUDY OF BIOLOGY.
ON THE
STUDY OF BIOLOGY.
It is my duty to-night to speak about the study
of Biology, and while it may be that there are
many of my audience who are quite familiar with
that study, yet as a lecturer of some standing,
it would, I know by experience, be very bad
policy on my part to suppose such to be exten-
sively the case. On the contrary, I must imagine
that there are many of you who would like to
know what Biology is ; that there are others who
have that amount of information, but would never-
theless gladly hear why it should be worth their
while to study Biology ; and yet others, again, to
whom these two points are clear, but who desire to
learn how they had best study it, and, finally,
when they had best study it.
I shall, therefore, address myself to the endeavour
to give you some answer to these four questions
— what Biology is ; why it should be studied ;
132 ON THE STUDY OF BIOLOGY.
how it should be studied ; and when it should be
studied.
In the first place, in respect to what Biology
is, there are, I believe, some persons who imagine
that the term " Biology " is simply a new-fangled
denomination, a neologism in short, for what used
to be known under the title of " Natural History; "
but I shall try to show you, on the contrary, that
the word is the expression of the growth of
science during the last 200 years, and came into
existence half a century ago.
At the revival of learning, knowledge was
divided into two kinds — the knowledge of nature
and the knowledge of man ; for it was the current
idea then (and a great deal of that ancient con-
ception still remains) that there was a sort of
essential antithesis, not to say antagonism, between
nature and man; and that the two had not very
much to do with one another, except that the
one was oftentimes exceedingly troublesome to
the other. Though it is one of the salient merits
of our great philosophers of the seventeenth
century, that they recognised but one scientific
method, applicable alike to man and to nature,
we find this notion of the existence of a broad
distinction between nature and man in the writings
both of Bacon and of Hobbes of Malmesbury ; and
I have brought with me that famous work which
NATURAL AND CIVIL HISTORY. 133
is now so little known, greatly as it deserves to
be studied, " The Leviathan," in order that I
may put to you in the wonderfully terse and
clear language of Thomas Hobbes, what was
his view of the matter. He sa)^s : —
" The register of knowledge of fact is called
history. Whereof there be two sorts, one called
natural history ; which is the history of such facts
or effects of nature as have no dependence on
man's will ; such as are the histories of metals,
plants, animals, regions, and the like. The other
is civil history ; which is the history of the
voluntary actions of men in commonwealths."
So that all history of fact was divided into
these two great groups of natural and of civil history.
The Royal Society was in course of foundation
about the time that Hobbes was writing this
book, which was published in 1651; and that
Society was termed a "Society for the Improve-
ment of Natural Knowledge," which was then nearly
the same thing as a " Society for the Improve-
ment of Natural History." As time went on,
and the various branches of human knowledofc
became more distinctly developed and separated
from one another, it was found that some were
much more susceptible of precise mathematical
treatment than others. The publication of the
"Principia" of Newton, which probably gave a
134 ON THE STUDY OF BIOLOGY.
greater stimulus to physical science than any work
ever published before, or which is likely to be
published hereafter, showed that precise mathe-
matical methods were applicable to those branches
of science such as astronomy, and what we now
call physics, which occupy a very large portion of
the domain of what the older writers understood
by natural history. And inasmuch as the partly
deductive and partly experimental methods of
treatment to which Newton and others subjected
these branches of human knowledge, showed
that the phenomena of nature which belonged
to them were susceptible of explanation, and
thereby came within the reach of what was called
" philosophy " in those days ; so much of this
kind of knowledge as was not included under
astronomy came to be spoken of as " natural philo-
sophy"— a term which Bacon had employed in
a much wider sense. Time went on, and yet
other branches of science developed themselves.
Chemistry took a definite shape ; and since all these
sciences, such as astronomy, natural philosophy,
and chemistry, were susceptible either of mathe-
matical treatment or of experimental treatment,
or of both, a broad distinction was drawn between
the experimental branches of what had previously
been called natural history and the observational
branches — those in which experiment was (or
BUFFON AND LINN^US. 135
appeared to be) of doubtful use, and where, at
that time, mathematical methods were inapplic-
able. Under these circumstances the old name
of "Natural History" stuck by the residuum, by
those phenomena which were not, at that time,
susceptible of mathematical or experimental treat-
ment ; that is to say, those phenomena of nature
which come now under the general heads of physical
geography, geology, mineralogy, the history of
plants, and the history of animals. It was in
this sense that the term was understood by the
great writers of the middle of the last century —
Buffon and Linnaeus — by Buffon in his great
work, the " Histoire Naturelle G6n6rale," and by
Linnaeus in his splendid achievement, the " Systema
Natura;." The subjects they deal with are spoken
of as " Natural History," and they called them-
selves and were called " Naturalists." But you
will observe that this was not the original meaning of
these terms ; but that they had, by this time, acquired
a signification widely different from that which they
possessed primitively.
The sense in which " Natural History " was
used at the time I am now speaking of has, to
a certain extent, endured to the present day.
There are now in existence in some of our
northern universities, chairs of " Civil and Natural
History," in which "Natural History" is used
136 ON THE STUDY OF BIOLOGY.
to indicate exactly what Hobbes and Bacon
meant by that term. The unhappy incumbent
of the chair of Natural History is, or was,
supposed to cover the whole ground of geology,
mineralogy, and zoology, perhaps even botany, in
his lectures.
But as science made the marvellous progress
which it did make at the latter end of the last and
the beginning of the present century, thinking men
beean to discern that under this title of " Natural
History " there were included very heterogeneous
constituents — that, for example, geology and mine-
ralogy were, in many respects, widely different
from botany and zoology ; that a man might
obtain an extensive knowledge of the structure
and functions of plants and animals, without
having need to enter upon the study of geology
or mineralogy, and vice versa; and, further as
knowledee advanced, it became clear that there was
a great analogy, a very close alliance, between those
two sciences of botany and zoology which deal with
living beings, while they are much more widely sepa-
rated from all other studies. It is due to Buffon to
remark that he clearly recognised this great fact
He says : " Ces deux genres d etres organises [les,
animaux et les vegetaux] ont beaucoup plus de
proprietes communes que de differences reelles.''
Therefore, it is not wonderful that, at the
LAMARCK AND TREVIRANUS. 137
beginning of the present century, in two different
countries, and so far as I know, without any
intercommunication, two famous men clearly con-
ceived the notion of uniting the sciences which
deal with living matter into one whole, and
of dealing with them as one discipline. In fact,
I may say there were three men to whom this
idea occurred contemporaneously, although there
were but two who carried it into effect, and only
one who worked it out completely. The persons
to whom I refer were the eminent physiologist
Bichat, and the great naturalist Lamarck, in France ;
and a distinguished German, Treviranus. Bichat^
assumed the existence of a special group of " physio-
logical '' sciences. Lamarck, in a work published
in 1801,^ for the first time made use of the name
" Biologie " from the two Greek words which
signify a discourse upon life and living things.
About the same time it occurred to Treviranus,
that all those sciences which deal with living
matter are essentially and fundamentally one, and
ought to be treated as a whole; and, in the year
1802, he published the first volume of what he
also called " Biologie." Treviranus's great merit
lies in this, that he worked out his idea, and
' See the distinction between the " sciences physiques " and the
"sciences physiologiques " in the " Anatomie Gdndrale," 1801.
» " Hydrogeologie," an. x. (1801).
7
138 ON THE STUDY OF BIOLOGY.
wrote the very remarkable book to which I refer. It
consists of six vohimes, and occupied its author
for twenty years — from 1802 to 1822.
That is the origin of the term " Biology ; " and
that is how it has come about that all clear thinkers
and lovers of consistent nomenclature have sub-
stituted for the old confusing name of " Natural
History," which has conveyed so many meanings,
the term " Biology " which denotes the whole of
the sciences which deal with living things, whether
they be animals or whether they be plants. Some
little time ago — in the course of this year, I think
— I was favoured by a learned classic, Dr. Field
of Norwich, with a disquisition, in which he
endeavoured to prove that, from a philological
point of view, neither Treviranus nor Lamarck
had any right to coin this new word " Biology "
for their purpose; that, in fact, the Greek word
" Bios " had relation only to human life and human
affairs, and that a different word was employed by
the Greeks when they wished to speak of the life
of animals and plants. So Dr. Field tells us we are
all wrong in using the term biology, and that we
ought to employ another ; only he is not quite
sure about the propriety of that which he proposes
as a substitute. It is a somewhat hard one —
" zootocology." I am sorry we are wrong, because
we are likely to continue so. In these matters
THE PROVINCE OF BIOLOGY. 139
we must have some sort of " Statute of Limitations."
When a name has been employed for half-a-century,
persons of authority^ have been using it, and its
sense has become well understood, I am afraid
that people will go on using it, whatever the weight
of philological objection.
Now that we have arrived at the origin of this
word " Biology," the next point to consider is :
What ground does it cover ? I have said that, in its
strict technical sense, it denotes all the phenomena
which are exhibited by living things, as distinguished
from those which are not living ; but while that
is all very well, so long as we confine ourselves to
the lower animals and to plants, it lands us in
considerable difficulties when we reach the higher
forms of livinof thino;s. For whatever view we
may entertain about the nature of man, one thing
is perfectly certain, that he is a living creature.
Hence, if our definition is to be interpreted strictiy,
we must include man and all his ways and works
under the head of Biology ; in which case, we
should find that psychology, politics, and political
economy would be absorbed into the province of
Biology. In fact, civil history would be merged
in natural history. In strict logic it may be hard
' " The term Bioloc^y^ which menns exactly what wc wish to express,
the Science of I.i/e, has often been used, and has of late become not
uncommon, among good writers." — Whcwell, " Philosophy of the
Inductive Sciences," vol. i. p. 5U (edition of 1847).
I40 ON THE STUDY OF BIOLOGY.
to object to this course, because no one can doubt
that the rudiments and outhnes of our own mental
phenomena are traceable among the lower animals.
They have their economy and their polity, and
if, as is always admitted, the polity of bees and the
commonwealth of wolves fall within the purview
of the biologist proper, it becomes hard to say
why we should not include therein human affairs,
which in so many cases resemble those of the bees
in zealous getting, and are not without a certain
parity in the proceedings of the wolves. The real
fact is that we biologists are a self-sacrificing people ;
and inasmuch as, on a moderate estimate, there are
about a quarter of a million different species of
animals and plants to know about already, we
feel that we have miore than sufficient territory.
There has been a sort of practical convention by
which we give up to a different branch of science
what Bacon and Hobbes would have called " Civil
History." That branch of science has constituted
itself under the head of Sociology. I may use
phraseology which, at present, will be well under-
stood and say that we have allowed that province
of Biology to become autonomous ; but I should like
you to recollect that that is a sacrifice, and that you
should not be surprised if it occasionally happens
that you see a biologist apparently trespassing in
the region of philosophy or politics ; or meddling
WHY BIOLOGY SHOULD BE STUDIED. 141
■with human education ; because, after all, that is
a part of his kingdom which he has only volun-
tarily forsaken.
Havinof now defined the meaning of the word
Biology, and having indicated the general scope of
Biological Science, I turn to my second question,
which is — Why should we study Biology ? Possibly
the time may come when that will seem a very odd
question. That we, living creatures, should not
feel a certain amount of interest in what it is that
constitutes our life will eventually, under altered
ideas of the fittest objects of hum.an inquiry, appear
to be a singular phenomenon ; but, at present,
judging by the practice of teachers and educators.
Biology would seem to be a topic that does
not concern us at all. I propose to put before
you a few considerations with which I dare say
many will be familiar already, but w^iich will
sufifice to show — not fully, because to demonstrate
this point fully would take a great many lectures
— that there are some very good and substantial
reasons why it may be advisable that we should
know something about this branch of human
learning.
I myself entirely agree with another sentiment of
the philosopher of Malmesbury, " that the scope of
all speculation is the performance of some action or
thing to be done," and I have not any very great
142 ON THE STUDY OF BIOLOGY.
respect for, or interest in, mere knowing as such.
I judge of the value of human pursuits by their
bearing upon human interests ; in other words, by
their utiHty ; but I should like that we should quite
clearly understand what it is that we mean by this
word "utility." In an Englishman's mouth it
generally means that by which we get pudding or
praise, or both. I have no doubt that is one
meaning of the word utility, but it by no means
includes all I mean by utility. I think that
knowledge of every kind is useful in proportion
as it tends to give people right ideas, which are
essential to the foundation of right practice, and to
remove wrong ideas, which are the no less essential
foundations and fertile mothers of every description
of error in practice. And inasmuch as, whatever
practical people may say, this world is, after all,
absolutely governed by ideas, and very often by the
wildest and most hypothetical ideas, it is a matter of
the very greatest importance that our theories of
things, and even of things that seem a long way
apart from our daily lives, should be as far as
possible true, and as far as possible removed from
error. It is not only in the coarser practical sense of
the word " utility," but in this higher and broader
sense, that I measure the value of the study of
biology by its utility ; and I shall try to point out to
you that you will feel the need of some knowledge
BIOLOGICAL VIEWS OF MAN. 143
of biology at a great many turns of this present
nineteenth century Hfe of ours. For example,
most of us attach great importance to the con-
ception which we entertain of the position of
man in this universe and his relation to the rest
of nature. We have almost all been told, and
most of us hold by the tradition, that man occupies
an isolated and peculiar position in nature ; that
though he is in the world he is not of the world;
that his relations to things about him are of a remote
character ; that his origin is recent, his duration
likely to be short, and that he is the great central
figure round which other things in this world
revolve. But this is not what the biologrist tells
us.
At the present moment j^ou will be kind enough
to separate me from them, because it is in no way
essential to my present argument that I should
advocate their views. Don't suppose that I am
saying this for the purpose of escaping the re-
sponsibility of their beliefs ; indeed, at other times
and in other places, I do not think that point has
been left doubtful ; but I want clearly to point out
to you that for my present argument they may all
be wrong ; and, nevertheless, my argument will hold
eood. The bioloofists tell us that all this is an
entire mistake. They turn to the physical orga-
nisation of man. They examine his whole structure,
144 ON THE STUDY OF BIOLOGY.
his bony frame and all that clothes it. They resolve
him into the finest particles into which the micro-
scope will enable them to break him up. They
consider the performance of his various functions
and activities, and they look at the manner in which
he occurs on the surface of the world. Then they
turn to other animals, and taking the first handy
domestic animal — say a dog — they profess to be
able to demonstrate that the analysis of the dog
leads them, in gross, to precisely the same results
as the analysis of the man ; that they find almost
identically the same bones, having the same re-
lations ; that they can name the muscles of the
dog by the names of the muscles of the man, and
the nerves of the dog by those of the nerves of
the man, and that, such structures and organs of
sense as we find in the man such also we find in
the dog ; they analyse the brain and spinal cord,
and they find that the nomenclature which fits the
one answers for the other. They carry their micro-
scopic inquiries in the case of the dog as far as
they can, and they find that his body is resolvable
into the same elements as those of the man. More-
over, they trace back the dog's and the man's
development, and they find that, at a certain stage
of their existence, the two creatures are not dis-
tinguishable the one from the other ; they find
that the dog and his kind have a certain distribution
THE SCALE OF BEING. i45
over the surface of the world, comparable in its
way to the distribution of the human species.
What is true of the dog they tell us is true of
all the higher animals ; and they assert that they
can lay down a common plan for the whole of
these creatures, and regard the man and the dog,
the horse and the ox as minor moditications of
one great fundamental unity. Moreover, the in-
vestigations of the last three-quarters of a century
have proved, they tell us, that similar inquiries,
carried out through all the different kinds of ani-
mals which are met with in nature, will lead us,
not in one straight series, but by many roads,
step by step, gradation by gradation, from man,
at the summit, to specks of animated jelly at the
bottom of the series. So that the idea of Leibnitz,
and of Bonnet, that animals form a great scale
of being, in which there are a series of gradations
from the most complicated form to the lowest and
simplest; that idea, though not exactly in the
form in which it was propounded by those philo-
sophers, turns out to be substantially correct. More
than this, when biologists pursue their investigations
into the vegetable world, they find that they can,
in the same way, follow out the structure of the
plant, from the must gigantic and complicated trees
down through a similar series of gradations, until
they arrive at specks of animated jelly, which they
146 ON THE STUDY OF BIOLOGY.
are puzzled to distinguish from those specks which
they reached by the animal road.
Thus, biologists have arrived at the conclusion
that a fundamental uniformity of structure pervades
the animal and vegetable worlds, and that plants
and animals differ from one another simply as
diverse modifications of the same ereat sreneral
plan.
Again, they tell us the same story in regard to
the study of function. They admit the large and
important interval which, at the present time, sepa-
rates the manifestations of the mental faculties,
observable in the higher forms of mankind, and
even in the lower forms, such as we know them,
from those exhibited by other animals ; but, at
the same time, they tell us that the foundations,
or rudiments, of almost all the faculties of man
are to be met with in the lower animals ; that
there is a unity of mental faculty as well as of
bodily structure, and that, here also, the diffe-
rence is a difference of degree and not of kind.
I said " almost all," for a reason. Among- the
many distinctions which have been drawn between
the lower creatures and ourselves, there is one
which is hardly ever insisted on,^ but which may
be very fitly spoken of in a place so largely devoted
' I think that my friend Professor AUman was the first to draw
attention to it.
KNOWLEDGE AND CRITICISM. 147
to Art as that in which we are assembled. It is
this, that while, among various kinds of animals,
it is possible to discover traces of all the other
faculties of man, especially the faculty of mimicry,
yet that particular form of mimicry which shows
itself in the imitation of form, either by modelling
or by drawing, is not to be met with. As far as
I know, there is no sculpture or modelling, and
decidedly no painting or drawing, of anim.al origin.
I mention the fact, in order that such comfort
may be derived therefrom as artists may feel
inclined to take.
If what the biologists tell us is true, it will be
needful to get rid of our erroneous conceptions
of man, and of his place in nature, and to sub-
stitute right ones for them. But it is impossible
to form any judgment as to whether the biologists
are right or wrong, unless we are able to appre-
ciate the nature of the arguments which they have
to offer.
One would almost think this to be a self-
evident proposition. I wonder what a scholar
would say to the man who should undertake to
criticise a difficult passage in a Greek play, but
who obviously had not acquainted himself with
the rudiments of Greek grammar. And yet, before
giving positive opinions about these high questions
of Biology, people not only do not seem to think
ON THE STUDY OF BIOLOGY.
it necessary to be acquainted with the grammar
of the subject, but they have not even mastered
the alphabet. You find criticism and denunciation
showered about by persons, who, not only have
not attempted to go through the discipline necessary
to enable them to be judges, but who have not even
reached that stage of emergence from ignorance
in which the knowledge that such a discipline is
necessary dawns upon the mind. I have had to
watch with some attention — in fact I have been
favoured with a good deal of it myself — the sort
of criticism with which biologists and biological
teachings are visited. I am told every now and
then that there is a " brilliant article " ^ in so-and-so,
in which we are all demolished. I used to read
these things once, but I am getting old now, and
I have ceased to attend very much to this cry of
" wolf" When one does read any of these pro-
ductions, what one finds generally, on the face of
it, is that the brilliant critic is devoid of even the
elements of biological knowledge, and that his
brilliancy is like the light given out by the crackling
of thorns under a pot of which Solomon speaks.
So far as I recollect, Solomon makes use of the
' Galileo was troubled by a sort of people whom he called " paper
philosophers," because they fancied that the true reading of nature
was to be detected by the collation of texts. The race is not extinct,
but, as of old, brings forth its " winds of doctrine " by which the
weathercock heads among us are much exercised.
KNOWLEDGE AND CRITICISM. 149
image for purposes of comparison ; but I will riot
proceed further into that matter.
Two things must be obvious : in the first place,
that every man who has the interests of truth at
heart must earnestly desire that every well-founded
and just criticism that can be made should be
made ; but that, in the second place, it is essential
to anybody's being able to benefit by criticism,
that the critic should know what he is talking
about, and be in a position to form a mental image
of the facts symbolised by the words he uses.
If not, it is as obvious in the case of a biological
argument, as it is in that of a historical or philological
discussion, that such criticism is a mere waste of
time on the part of its author, and wholly unde-
serving of attention on the part of those who are
criticised. Take it then as an illustration of the
importance of biological study, that thereby alone
are men able to form something like a rational
conception of what constitutes valuable criticism of
the teachings of biologists.^
' Some critics do not even take the trouble to read. I have recently
been adjured with much solemnity, to state publicly why I have
" changed my opinion " as to the value of the palaiontological evidence
of the occurrence of evolution.
To this my reply is, Why should I, when that statement was made
seven years ago? An address delivered from the Presidential Chair
of the Geological Society, in 1870, may be said to be a public document,
inasmuch as it not only appeared in the Journal of that learned body,
I50 ON THE STUDY OF BIOLOGY.
Next, I may mention another bearing of biolo-
gical knowledge— a more practical one in the
ordinary sense of the word. Consider the theory
of infectious disease. Surely that is of interest
to all of us. Now the theory of infectious disease
is rapidly being elucidated by biological study. It
is possible to produce, from among the lower
animals, examples of devastating diseases which
spread in the same manner as our infectious disorders,
and which are certainly and unmistakably caused by
living organisms. This fact renders it possible,
at any rate, that that doctrine of the causation of
infectious disease which is known under the name
of " the germ theory " may be well-founded ; and,
if so, it must needs lead to the most important
practical measures in dealing with those terrible
visitations. It may be well that the general, as
well as the professional, public should have a
sufficient knowledge of biological truths to be able
but was re-published, in 1873, in a volume of " Critiques and Addresses,"
to which my name is attached. Therein will be found a pretty full
statement of my reasons for enunciating two propositions : (i) that
" when we turn to the higher Vertebrata, the results of recent in-
vestigations, however we may sift and criticise them, seem to me to
leave a clear balance in favour of the evolution of living forms one
from another ; " and (2) that the case of the horse is one which " will
stand rigorous criticism."
Thus I do not see clearly in what way I can be said to have changed
my opinion, except in the way of intensifying it, when in consequence
of the accumulation of similar evidence since 1870, I recently spoke of
the denial of evolution as not worth serious consideration.
PRACTICAL KNOWLEDGE. 151
to take a rational interest in the discussion of
such problems, and to see, what I think they may-
hope to see, that,- to those who possess a sufficient
elementary knowledge of Biolog)^, they are not
all quite open questions.
Let me mention another important practical
illustration of the value of biological study. Within
the last forty years the theory of agriculture has
been revolutionised. The researches of Liebig,
and those of our own Lawes and Gilbert, have
had a bearing upon that branch of industry the
importance of which cannot be overestimated ; but
the whole of these new views have grown out of
the better explanation of certain processes which
go on in plants ; and which, of course, form a part
of the subject-matter of Biology.
I might go on multiplying these examples, but
I see that the clock won't wait for me, and I
must therefore pass to the third question to which
I referred : — Granted that Biology is something
worth studying, what is the best way of studying
it ? Here I must point out that, since Biology is
a physical science, the method of studying it must
needs be analogous to that which is followed in
the other physical sciences. It has now long been
recosfnised that, if a man wishes to be a chemist,
it is not only necessary that he should read chemi-
cal books and attend chemical lectures, but that
152 ON THE STUDY OF BIOLOGY.
he should actually perform the fundamental experi-
ments in the laboratory for himself, and thus learn
exactly what the words which he finds in his books
and hears from his teachers, mean. If he does
not do so, he may read till the crack of doom,
but he will never know much about chemistry.
That is what every chemist will tell you, and the
physicist will do the same for his branch of science.
The great changes and improvements in physical
and chemical scientific education, which have taken
place of late, have all resulted from the combina-
tion of practical teaching with the reading of books
and with the hearinor of lectures. The same thino-
is true in Biology. Nobody will ever know any-
thing about Biology except in a dilettante " paper-
philosopher" way, who contents himself with read-
ing books on botany, zoology, and the like ; and
the reason of this is simple and easy to under-
stand. It is that all language is merely symbolical
of the things of which it treats ; the more com-
plicated the things, the more bare is the symbol,
and the more its verbal definition requires to be
supplemented by the information derived directly
from the handling, and the seeing, and the touch-
ing of the thing symbolised : — that is really what
is at the bottom of the whole matter. It is plain
common sense, as all truth, in the long run, is only
common sense clarified. If you want a man to
TYPICAL FORMS, 153
be a tea merchant, you don't tell him to read books
about China or about tea, but you put him into
a tea-merchant's office where he has the handlino-,
the smelling, and the tasting of tea. Without the
sort of knowledge which can be gained only in
this practical way, his exploits as a tea merchant
will soon come to a bankrupt termination. The
" paper-philosophers " are under the delusion that
physical science can be mastered as literary ac-
complishments are acquired, but unfortunately it is
not so. You may read any quantity of books,
and you may be almost as ignorant as you were
at starting, if you don't have, at the back of your
minds, the change for w^ords in definite images
which can only be acquired through the operation
of your observing faculties on the phenomena of
nature.
It may be said : — " That is all very well, but
you told us just now that there are probably some-
thing like a quarter of a million different kinds
of living and extinct animals and plants, and a
human life could not suffice for the examination
of one-fiftieth part of all these." That is true,
but then comes the great convenience of the way
things are arranged ; which is, that although there
are these immense numbers of different kinds of
living things in existence, yet they are built up,
after all, upon marvellously few plans.
154 ON THE STUDY OF BIOLOGY.
There are certainly more than 100,000 species of
insects, and yet anybody who knows one insect
— if a properly chosen one — will be able to have
a very fair conception of the structure of the
whole. I do not mean to say he will know
that structure thoroughly, or as well as it is desir-
able he should know it ; but he will have enough
real knowledge to enable him to understand what
he reads, to have genuine images in his mind of
those structures which become so variously modi-
fied in all the forms of insects he has not seen.
In fact, there are such things as types of form
among animals and vegetables, and for the pur-
pose of getting a definite knowledge of what con-
stitutes the leadinof modifications of animal and
plant life, it is not needful to examine more than
a comparatively small number of animals and
plants .
Let me tell you what we do in the biological
laboratory which is lodged in a building adjacent to
this. There I lecture to a class of students daily
for about four-and-a-half months, and my class have,
of course, their text-books ; but the essential part
of the whole teaching, and that which I regard
as really the most important part of it, is a
laboratory for practical work, which is simply a
room with all the appliances needed for ordinary
dissection. We have tables properly arranged in
TYPICAL FORMS. i55
regard to light, microscopes, and dissecting instru-
ments, and we work through the structure of a
certain number of animals and plants. As, for
example, among the plants, we take a yeast plant,
a Proiococc2is, a common mould, a Chara, a fern,
and some flowermg plant ; among animals we ex-
amine such things as an Amoeba, a Vorticella^ and
a fresh- water polype. We dissect a star- fish, an
earth-worm, a snail, a squid, and a fresh-water
mussel. We examine a lobster and a cray-fish,
and a black beetle. We go on to a common skate,
a cod-fish, a frog, a tortoise, a pigeon, and a rabbit,
and that takes us about all the time we have to
give. The purpose of this course is not to make
skilled dissectors, but to give every student a clear
and definite conception, by means of sense-images,
of the characteristic structure of each of the lead-
ing modifications of the animal kingdom ; and
g^'-lhat is perfectly possible, by going no further than
the leneth of that list of forms which I have
enumerated. If a man knows the structure of
the animals I have mentioned, he has a clear and
exact, however limited, apprehension of the essen-
tial features of the organisation of all those great
divisions of the animal and vegetable kingdoms
to which the forms I have mentioned severally
belong. And it then becomes possible for him
to read with profit ; because every time he meets
156 ON THE STUDY OF BIOLOGY.
with the name of a structure, he has a definite
image in his mind of what the name means in
the particular creature he is reading about, and
therefore the reading is not mere reachng. It is
not mere repetition of words ; but every term
employed in the description, we will say, of a horse,
or of an elephant, will call up the image of the
things he had seen in the rabbit, and he is able to
form a distinct conception of that which he has
not seen, as a modification of that which he has
seen.
I find this system to yield excellent results ; and
I have no hesitation whatever in saying, that any
one who has gone through such a course, atten-
tively, is in a better position to form a conception
of the great truths of Biology, especially of mor-
phology (which is what we chiefly deal with), than
if he had merely read all the books on that topic
put together.
The connection of this discourse with the Loan
Collection of Scientific Apparatus arises out of the
exhibition in that collection of certain aids to our
laboratory work. Such of you as have visited that
very interesting collection may have noticed a series
of diagrams and of preparations illustrating the
structure of a frog. Those diagrams and prepara-
tions have been made for the use of the students
in the biological laboratory. Similar diagrams and
NATURAL HISTORY MUSEUMS. 157
preparations Illustrating the structure of all the
other forms of life we examine, are either made or
in course of preparation. Thus the student has
before him, first, a picture of the structure he ought
to see ; secondly, the structure itself worked out ;
and if with these aids, and such needful explana-
tions and practical hints as a demonstrator can
supply, he cannot make out the facts for himself
in the materials supplied to him, he had better
take to some other pursuit than that of biological
science.
I should have been glad to have said a few words
about the use of museums in the study of Biology,
but I see that my time is becoming short, and I
have yet another question to answer. Nevertheless
I must, at the risk of wearying you, say a word
or two upon the important subject of museums.
Without doubt there are no helps to the study of
Biology, or rather to some branches of it, which
are, or may be, more important than natural history
museums ; but, in order to take this place in regard
to Biology, they must be museums of the future.
The museums of the present do not, by any
means, do so much for us as they might do. I do not
wish to particularise, but I dare say many of you,
seeking knowledge, or in the laudable desire to
employ a holiday usefully, have visited some great
natural history museum. You have walked through
158 ON THE STUDY OF BIOLOGY.
a quarter of a mile of animals, more or less well
stuffed, with their long names written out underneath
them ; and, unless your experience is very different
from that of most people, the upshot of it all is
that you leave that splendid pile with sore feet, a
bad headache, and a general idea that the animal
kingdom is a "mighty maze without a plan." I
do not think that a museum which brings about
this result does all that may be reasonably expected
from such an institution. What is needed in a collec-
tion of natural history is that it should be made
as accessible and as useful as possible, on the one
hand to the general public, and on the other to
scientific workers. That need is not met by con-
structing a sort of happy hunting-ground of miles
of glass cases ; and, under the pretence of exhibiting
everything, putting the maximum amount of obstacle
in the way of those who wish properly to see
anything.
What the public want is easy and unhindered
access to such a collection as they can understand
and appreciate ; and what the men of science want
is similar access to the materials of science. To
this end the vast mass of objects of natural history
should be divided into two parts — one open to the
public, the other to men of science, every day.
The former division should exemplify all the more
important and interesting forms of life. Explana-
THE MUSEUM OF THE FUTURE. 159
tory tablets should be attached to them, and cata-
logues containing clearly-written popular expositions
of the general significance of the objects exhibited
should be provided. The latter should contain,
packed into a comparatively small space, in rooms
adapted for working purposes, the objects of purely
scientific interest. For example, we will say I am
an ornithologist. I go to examine a collection of
birds. It is a positive nuisance to have them
stuffed. It is not only sheer waste, but I have to
reckon with the ideas of the bird-stuffer, while, if
I have the skin and nobody has interfered with it,
I can form my own judgment as to what the bird
was like. For ornithological purposes, what is
needed is not glass cases full of stuffed birds on
perches, but convenient drawers into each of which
a great quantity of skins will go. They occupy
no great space and do not require any expenditure
beyond their original cost. But for the edification of
the public, who want to learn indeed, but do not
seek for minute and technical knowledge, the case
is different. What one of the general public walk-
ing into a collection of birds desires to see is not
all the birds that can be got together. He does
not want to compare a hundred species of the
sparrow tribe side by side ; but he wishes to know
what a bird is, and what are the great modifications
of bird structure, and to be able to get at that
i6o ON THE STUDY OF BIOLOGY.
knowledge easily. What will best serve his purpose
is a comparatively small number of birds carefully
selected, and artistically, as well as accurately, set
up ; with their different ages, their nests, their
young, their eggs, and their skeletons side by side ;
and in accordance with the admirable plan which
is pursued in this museum, a tablet, telling the
spectator In legible characters what they are and
what they mean. For the instruction and recreation
of the public such a typical collection would be of
far greater value than any many-acred imitation
of Noah's ark.
Lastly comes the question as to when biological
study may best be pursued, I do not see any
valid reason why it should not be made, to a
certain extent, a part of ordinary school train-
ing. I have lono^ advocated this view, and I
am perfectly certain that it can be carried out
with ease, and not only with ease, but with
very considerable profit to those who are taught ;
but then such instruction must be adapted to
the minds and needs of the scholars. They used
to have a very odd way of teaching the classical
languages when I was a boy. The first task set
you was to learn the rules of the Latin grammar
in the Latin language — that being the language you
were going to learn ! I thought then that this
was an odd way of learning a language, but did
ELEMENTARY INSTRUCTION. i6i
not venture to rebel against the judgment of my
superiors. Now. perhaps, I am not so modest as
I was then, and I allow myself to think that it was
a very absurd fashion. But it would be no less
absurd, if we were to set about teaching Biology
by putting into the hands of boys a series of
definitions of the classes and orders of the animal
kingdom, and making them repeat them by heart.
That is so very favourite a method of teaching,
that I sometimes fancy the spirit of the old clas-
sical system has entered into the new scientific
system, in which case I would much rather that any
pretence at scientific teaching were abolished alto-
gether. What really has to be done is to get into
the young mind some notion of what animal and
vegetable life is. In this matter, you have to con-
sider practical convenience as well as other things.
There are difficulties in the way of a lot of boys
makinor messes with slug-s and snails ; it mif^ht not
work in practice. But there is a very convenient
and handy animal which everybody has at hand,
and that is himself; and it is a very easy and
simple matter to obtain common plants. Hence
the general truths of anatomy and physiology can
be taught to young people in a very real fashion
by dealing with the broad facts of human structure.
Such viscera as they cannot very well examine in
8
i62 ON THE STUDY OF BIOLOGY.
themselves, such as hearts, lungs, and livers, may
be obtained from the nearest butcher's shop. In
respect to teaching something about the biology of
plants, there is no practical difficulty, because almost
any of the common plants will do, and plants do
not make a mess — at least they do not make an
unpleasant mess ; so that, in my judgment, the best
form of Biology for teaching to very young people
is elementary human physiology on the one hand,
and the elements of botany on the other ; beyond
that I do not think it will be feasible to advance
for some time to come. But then I see no reason
why, in secondary schools, and in the Science
Classes which are under the control of the Science
and Art Department — and which I niay say, in
passing, have, in my judgment, done so very much
for the diffusion of a knowledge of science over
the country — we should not hope to see instruction
in the elements of Biology carried out, not perhaps
to the same extent, but still upon somewhat the
same principle as here. There is no difficulty,
when you have to deal with students of the ages
of 15 or 1 6, in practising a little dissection and in
getting a notion of, at any rate, the four or five
great modifications of the animal form ; and the
like is true in regard to the higher anatomy of
plants.
ADVICE TO PAPER-PHILOSOPHERS. 163
While, lastly, to all those who are studyin_i»- bio- (
logical science with a view to their own edification
merely, or with the intention of becominc^ zooloj^ists
or botanists ; to all those who intend to pursue
physioloi^y — and especially to those who propose
to employ the workini^ years of thf.-ir ]iv(;s in the S
practice of medicine — I say that there is no traininj^ ;
so fitted, or which may be of such important [
service to them, as the discipline in practical /
bi(jlo_L(ical work which I have sketched out as being >
pursued in the laboratory hard by. ^
I may add that, beyond all tliese diffc^rent classes
of persons who may profit by the study of Biolog'y,
there is yet one other. I remember, a number of
years ag'o, that a [gentleman who was a vehement
opponent of Mr, Darwin's views and had written
some terrible articles against them, applied to me '
to know what was thf^ best way in which he could
acquaint himself with the strongest arguments in
favour of evolution. I wrote back, in all good faith ,
and simplicity, recommending him to go through a \
course of comparative anatomy and physiology, and ^
then to study development. I am sorry to say he
was very much displeaso^d, as people often are with
good advice. Notwithstanding this discouraging
result, I venture, as a parting word, to repeat the
i64 ON THE STUDY OF BIOLOGY.
suggestion, and to say to all the more or less acute
lay and clerical " paper-philosophers " ^ who venture
into the regions of biological controversy — Get a
little sound, thorough, practical, elementary instruc-
tion in biology.
' Writers of this stamp are fond of talking about the Baconian
method. I beg them therefore to lay to heart these two weighty
sayings of the herald of Modern Science : —
"Syllogismus ex propositionibus constat, propositiones ex verbis,
verba notionum tesserae sunt. Itaque si notiones ipsse (id quod basis
rei est) confusse sint et temere a rebus abstractae, nihil in iis quce
superstruuntur est firmitudinis." — " Novum Organon," ii. 14.
" Huic autem vanitati nonnulli ex modernis summa levitate ita
indulserunt, ut in primo capitulo Geneseos et in libro Job et aliis
scripturis sacris, philosophiam naturalem fundare conati sint ; i7iler
vivos qtiarentes mortua." — Ibid., 65.
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